The Taoiseach has reiterated that the Government is open to alternatives to the backstop, but they must be realistic, legally binding and workable in practice.
In a speech to a British-Irish Chamber of Commerce dinner in Dublin, Leo Varadkar said no such proposals have been received to date.
Mr Vardakar said avoiding the return of a hard border on this island is a Government priority in all circumstances and that peace on the island and the success of the all-island economy must be protected.
"This is why the backstop continues to be a critical component of the Withdrawal Agreement, unless and until an alternative is found," he said.
He added that a Withdrawal Agreement that does not include the backstop is no good for Ireland as it merely "kicks the can down the road" until the transition phase ends.
The Taoiseach told the gathering that political developments in the UK mean there is a significant and growing risk of a no deal Brexit.
He said the Government's preferred outcome is a deal based on the Withdrawal Agreement.
Government efforts will continue to avoid a crash out Brexit, he added, but not "at any cost."
Whatever happens, Ireland will not be dragged out of the Single European Market, he stated.
Mr Varadkar added that unlike some people, he does not see upsides to a No Deal.
He said he does fear it, but claimed that he is prepared for it politically.
Government contingency planning has identified that some sectors have low levels of Brexit preparedness, he said, with smaller and independent businesses, as well as retail and construction sectors particularly underprepared.
That needs to change, the Taoiseach stated, and all businesses need to listen to the advice and help on offer.
Even if the UK leaves the EU on 31 October, that will not be the end of the story, the Taoiseach warned.
If there is a deal, a new difficult and fraught phase will begin involving several years of negotiations on a new free trade agreement and an economic and security partnership.
A no-deal, on the other hand, which could last for a period, will also require negotiations to begin again he claimed, with the first and only items on the agenda being citizens' rights, the financial settlement with the EU and a solution to the Irish Border.
"All the issues we spent the last two years on," he remarked.
Despite the challenges and permanent changes in the political and economic environment, the Taoiseach expressed the view that Ireland can withstand the challenge.
"The UK is geographically and culturally our closest neighbour and will continue to be a vital trading partner, no matter what shape Brexit takes," he said.
He said certain things like the Common Travel Area and the rights of Irish and Dual British-Irish citizens in Northern Ireland and Britain to travel, work, do business and study through the EU without a visa or permit will not change.
Significant changes in medicine supplies are not anticipated, and food will remain on shelves, although possibly not all the same brands, he added.
Mr Vardakar said there will have to be checks on goods and live animals and, as far as possible, they will take place in ports, airports and at businesses, although some may take place near the border.
The details of this are currently being worked out with the European Commission, he said.
Taxes would have to be paid on goods bought from the UK and EU consumer protections will no longer apply, he said.
Tariffs will also apply to goods imported into Ireland from the UK, he warned, and vice versa, and importers and exporters will need to make customs declarations.
Flights, trains and business will continue to operate normally for a period, the Taoiseach stated, but a permanent agreement would be required.
He added that while a no-deal Brexit will have adverse effects on the economy here, a recession is not anticipated and as a result there will be no need for tax increases, spending cuts or reduction in pay, pensions or welfare.
'Nobody should be surprised' by no-deal implications - Coveney
Earlier, the Tánaiste and Minister for Foreign Affairs Simon Coveney said Tuesday night's briefing to Cabinet was not his first on the potential impact of a no-deal Brexit, so nobody should be surprised that there are vulnerable sectors such as fishing, agri-food or tourism.
His comments come following newspaper reports that some ministers were taken aback by the severity of the warnings he gave yesterday.
Speaking in Cork, he said that no report he gave at the Cabinet meeting referred to a figure of 10,000 job losses in three months in the tourism and hospitality sectors in the event of a no-deal.
However, he said it was important to level with people and feels he has always been straight up in terms of the impact of a no-deal Brexit, and why it should be avoided because everyone loses in a no-deal scenario.
Mr Coveney said the onus was on the UK government, who now want the backstop removed from the Withdrawal Agreement, to put forward an alternative, but that has yet to be given.
"They want the backstop removed from the Withdrawal Agreement, we know that that creates huge problems and the onus is on the UK who are looking to change things to be able to put an alternative that solves those problems on the table and we haven't got that yet," he said.
Asked about any potential border arrangements, Mr Coveney said that the Government had some sense of arrangements, but did not have the detail yet, as it had not been agreed with the European Commission.
The Tánaiste said the public would know once he knew.
"As soon as we know, you will know because this is not just an Irish border we are talking about, it is also an EU frontier with the UK so the solution has to be worked out collectively with Ireland and the EU," he said.
"It needs to take into account the unique circumstances on this island and the unique circumstances in Northern Ireland, and we need a dual objective here - to protect Ireland's place in the single market so that we don't get dragged out of the single market against our will as a result of Brexit, and secondly, we have to try and do all we can to protect the all-Ireland economy as it function."
Commenting on the strengthening of sterling yesterday, Mr Coveney said it was more about a no-deal Brexit being marginally less likely than it was before the votes at Westminster over the past 24 hours.
Asked about the British Prime Minister's intended visit on Monday, Mr Coveney said his understanding is that he is coming on Monday morning and he has no reason to believe that this will not happen.
Elsewhere, Minister for Finance and Public Expenditure Paschal Donohoe said the risk of a no-deal Brexit had "grown" in recent days amid continued turmoil in the UK parliament.
Mr Donohoe also warned of the need to maintain a "stable political environment" in Ireland, while it waits for the British government to make a final decision on what it will do about Brexit and when it will leave the EU.
Speaking in Waterford after attending a council presentation on regional infrastructure projects, Mr Donohoe said: "I believe that the risk of a no-deal Brexit has grown.
"Of course it is a significant development to see that within the current House of Commons, there is a majority there that is in favour of avoiding a no-deal Brexit, but of course it's equally apparent to all of us that that there's a really high level of uncertainty and volatility now afoot in British politics."
Mr Donohoe's comments came after a night of further House of Commons defeat for Prime Minister Boris Johnson, with MPs backing legislation to try to prevent a no-deal Brexit, and not backing in sufficient numbers Mr Johnson's call for an October election.
The visit of Mr Johnson to Dublin next Monday to meet Taoiseach Leo Varadkar would be "really important" in that context, Mr Donohoe said.
He added: "But as we're looking at uncertainty developing there, as we're looking at risk growing there, it's very important that the stable political environment that we have here in Ireland be maintained.
"It will be maintained, our sole political focus is on doing all we can to try and get Ireland ready to deal with consequences that might develop after the end of October."
Mr Donohoe said he and his Cabinet colleagues were "well aware of what will be the employment consequences of a no-deal Brexit," and reiterated the Government's warning from earlier this year that, in that eventuality, "up to 50,000 jobs would not be created in our economy that would otherwise be created".
Next month's Budget will involve him "outlining the supports and the plans that we will put in place to deal with the consequences of a no-deal Brexit if we get to that point," he said.
Asked if he thinks there will be border checks in place in six months' time, the minister said: "All that depends on the decisions that are made by the British government in the coming weeks."
Elsewhere, the British minister in charge of no-deal preparations has said he had not talked to members of the Irish Government about what will happen on the border in a no-deal Brexit.
Michael Gove told a House of Commons committee that no tariffs would be collected on goods moving from Ireland to Northern Ireland in a no-deal scenario.
Sinn Féin leader Mary Lou McDonald has said Ireland must not lose its nerve as a potential no-deal Brexit draws nearer.
Speaking on RTÉ's News at One, Ms McDonald said that we need to maintain focus and not get tied up in "the theatrics of the zoo that is Westminster".
Ms McDonald also called on the Government to be more forthcoming with information about Brexit.
She also said the Government should not think its way into a position where it is making a choice between the single market and the Good Friday Agreement, and also said her party has begun preparations for a potential general election at Westminster.