Sinn Féin has said it will have further discussions on a Northern Ireland budget paper circulated by the finance minister proposing cuts of up to £872m.
On Monday, Finance Minister Simon Hamilton said cuts of £700m would be a "conservative enough estimate" but the figure is now understood to be higher.
If next year's draft budget is not agreed by Friday, Stormont will lose out on a £100m loan from the Treasury.
Sinn Féin said the executive is facing "very difficult decisions".
A spokesman for the party said what he called "the Tory cuts to public services" were an "ideologically driven assault on the welfare state" and were at the heart of the financial crisis the Northern Ireland Executive is facing.
However, despite the reduced funding, the party would continue to work to reach an agreement on a budget "which defends core public services, particularly health and education".
The finance minister said he believed the education budget could no longer be protected from cuts.
The education ministry is held by Sinn Féin, but so far the party has given no indication it is prepared to accept the proposals contained in Mr Hamilton's paper.
Without agreement between Sinn Féin and the Democratic Unionist Party the budget could not be passed.
Northern Ireland Secretary Theresa Villiers has said the job of resolving budget questions would be taken from the Stormont parties, unless they agree a draft budget by the end of the month.
Ms Villiers said that while there was some flexibility in the process of consultation, it was crucial the parties stuck to the timetable.
"Unless they get on and agree a draft budget, ultimately when we get to April, we'll end up with civil servants making the allocations on budgets," she said.
"We'll end up with a situation where Northern Ireland's elected leaders have the power to resolve budget questions taken from them," she added.