A Christmas bonus will be paid to all welfare recipients including the majority, but not all, of those on the Pandemic Unemployment Payment (PUP).
The move means thousands of pensioners, people on disability payments and those who became unemployed before and after the pandemic hit will see their weekly payment increase in the lead up to Christmas.
However, not everyone on the PUP will receive the top-up.
It is understood around 90pc of those who are currently in receipt of the payment will receive the bonus.
Ordinarily, a person must be on a welfare support for 15 months to qualify for the Christmas bonus.
This would mean thousands of people who became unemployed due to the Covid-19 pandemic would miss out on the bonus payment.
However, the Government has decided to reduce this to four months to allow those on the pandemic support to receive the top up this year.
The four-month threshold does not have to be concurrent and a recipient of the PUP who was unemployed at the start of the Covid-19 outbreak but retuned to work before losing their job again can still qualify.
However, people who recently became unemployed due to the Government's increased coronavirus restrictions will miss out on the payment.
Anyone who loses their job between now and Christmas will also miss out.
Social Protection Minister Heather Humphreys and Public Expenditure and Reform Minister Michael McGrath are understood to have reached the deal yesterday evening.
The total cost of the budget measure is over €650m.
Justice Minister Helen McEntee has also secured significant funding to increase the number of garda recruits by 600 along with an additional 500 civilian members of the force.
Last night, the minister was also in negotiations with Mr McGrath over funding for 70 new garda vehicles.
Ms McEntee is hoping to buy the new fleet to replace the rental cars gardaí have been using during the pandemic.
The minister's budget for the force is significant given the rising costs of the pandemic and the potential implications of Brexit.
Elsewhere, motorists driving high carbon-emitting vehicles are to be hit hard in today's Budget.
Motor tax and VRT, along with the cost of diesel and petrol, are all set to rise as part of a Government plan to discourage people from driving cars with high emissions.
Motor tax is expected to increase by as much as €50 a year for some drivers of high-polluting cars, while it is due to decrease for those who drive zero-emission cars.
The changes will see 88pc of motorists escape increased taxes, but 7pc of drivers of mostly older vehicles will have to pay an extra €10 a year.
Another 4pc of motorists who own high-polluting vehicles will pay between €30 to €50 extra.
Increases in motor tax are being introduced in line with climate action commitments and will encourage motorists to move away from higher-polluting vehicles.
The move will be seen as big win for the Green Party but is likely to result in a backlash for Fianna Fáil and Fine Gael.
Meanwhile, the cost of petrol and diesel is set to rise after the Budget due to a €7.50 increase in the carbon tax.
That will add €1.30 to an average 60-litre tank of petrol and €1.51 to a tank of diesel.