Minister for Finance Paschal Donohoe has ruled out any reductions in personal taxation in the next Budget.
Mr Donohoe was speaking after the Cabinet agreed to base Budget 2020 on the assumption that there will be a no-deal Brexit.
He said this decision would provide certainty to businesses, safeguard the public finances and prevent the reversal of decisions later on.
The minister also said the welfare package this year would not be similar in scale to previous years.
Mr Donohoe will announce the full details of the Budget in the Dáil on 8 October.
The Government is likely to seek to have State-aid rules eased in an effort to offer financial assistance to businesses that would suffer most if there was a hard Brexit.
"Assuming a no-deal Brexit ensures the Government has the necessary resources at its disposal to meet the impact of this exceptional challenge whilst preserving the longer term sustainability of the public finances."
Mr Donohoe also said that increases will be made to social welfare payments.
He added: "The government will, of course, put in place the resources that are needed to support citizens at a time of change and difficulty, and to put in place the provision that may be needed to accommodate a reduced tax take due to fewer people at work.
"We will also have the provision in place to increase social welfare supports and funding due to a temporary increase in unemployment.
"We will also, in that phase of the budget, introduce timely, targeted and temporary measures for the sectors of our economy that could be, and will be, affected by a no-deal Brexit taking place."
In what he described as a "safe and careful budget", Mr Donohoe said it will focus on ensuring the government has the resources it needs to be ready for a shock at the end of October when the UK is due to leave the European Union.
"I want to ensure that we are maximising the resources that are available to help citizens, families and communities that could find themselves dealing with real change as a result of a no-deal Brexit taking place.
"I will have to make changes in our personal tax code to deal with a potential change in the minimum wage.
"There are the kinds of changes that I still want to ensure that I make but my priority is going to be making our national finances as robust as possible to ensure that if we do face a challenge in 2020 that we are best placed as possible to deal with it."
Scheme to help those in mortgage arrears to be extended
The Government is also expected to extend for three years a scheme to help those in mortgage arrears.
The Abhaile scheme, set up in 2016, has provided financial advice and negotiation support to more than 12,000 households at risk of losing their homes.
Figures show that more than 30% of all borrowers who have been advised by Abhaile have a solution in place.
However, there are still an estimated 22,000 homes in long-term mortgage arrears.
This morning, Minister for Social Protection Regina Doherty and Minister for Justice Charlie Flanagan were due to ask the Cabinet to extend the scheme.
They expect to allocate €17.27m over the next three years.
The most recent homeless figures show that there are now 10,275 adults and children in emergency accommodation.