DUP MP Jeffrey Donaldson has said he does not think the Taoiseach is acting in Ireland's interest on Brexit, as he knows a no-deal Brexit is on its way unless Britain's concerns on the backstop are addressed.
Speaking on RTÉ's Morning Ireland, Mr Donaldson said that a timescale for the backstop needed to be set in place to put MPs' concerns at ease.
"I disagree that the Taoiseach is acting in Ireland’s interests, when he knows that we are heading towards a no-deal outcome unless we can address the concern about the backstop, and the timescale for the backstop," he said.
"I don't think that it is a huge ask at the end of the day to avoid a no-deal outcome," he added.
He said the only remaining issue on Brexit is that the Irish Government must address the backstop, and once done they can move on to addressing the future relationship.
Mr Donaldson said the reason we have an impasse is because on three occasions the UK parliament would not approve the Withdrawal Agreement because of the backstop.
He said it was a concern that was shared across a number of parties in Westminster and said given Ireland's refusal to discuss the backstop, we were heading for a no-deal Brexit.
In response, the Taoiseach said that he disagreed with Mr Donaldson's analysis.
Speaking to reporters this evening, he said: "Ultimately, Brexit is about the UK leaving the European Union.
"So the Withdrawal Agreement can only ever be a treaty and negotiation, therefore, between the EU on the one side and the UK on the other.
"When it comes to the future relationship treaty, it's going to be the same. It's going to be the EU on one side and the UK on the other.
"Ireland is part of the European Union and that gives us a position of strength."
Mr Donaldson said an agreement is only an agreement if both sides sign up to it, and when questioned about Theresa May signing up to it, he said she was the prime minister but was not the government.
He said we could wish all we want that the problem would go away but it will not.
Mr Donaldson said all they were asking for was confirmation that the backstop was temporary by putting a time limit on it.
Earlier, a Government spokesperson said: "The Government's objectives on Brexit have focused on the need to protect the Good Friday Agreement, the peace process, and to avoid a hard border on the island of Ireland. These objectives are shared by our EU partners.
"The Brexit negotiations were a bilateral negotiation between the EU and the UK government led by PM May, with Ireland's concerns and interests represented in the EU position. In those negotiations, our objectives were pursued and eventually secured in the Withdrawal Agreement.
"The protocol on Ireland and Northern Ireland, is a fair and balanced deal, which has involved compromises on both sides.
"It delivers on the shared objective of providing a guarantee that a hard border will be avoided while ensuring that nothing in this agreement will prejudice the constitutional status of Northern Ireland and the principle of consent as set out in the Good Friday Agreement.
"The need for a backstop is supported by many voters, farmers, businesses and communities across Northern Ireland, as was confirmed in the recent European elections."
Elsewhere, Conservative Party leadership race frontrunner Boris Johnson has claimed it is "perfectly realistic" to renegotiate the Withdrawal Agreement to allow Britain to leave the European Union in October.
The former foreign secretary told BBC Radio 4's World At One programme that he was committed to leaving the EU by 31 October.
Mr Johnson said the backstop problems could be solved by having checks away from the border.
"There is a clear way that the now effectively defunct Withdrawal Agreement can be disaggregated - the good bits of it can be taken out."
"All those that say we should delay [Brexit], risk doing terminal damage to trust in politics – we’ve got to be out by October 31st"— The World at One (@BBCWorldatOne) June 14, 2019
The Conservative Leadership candidate @BorisJohnson breaks his silence and talks to @BBCWorldatonehttps://t.co/du7P9bVtrg pic.twitter.com/WOii7XIkTR