Sinn Fein insist they want a deal with the DUP to restore power-sharing in the North, but can't stagger from one crisis to another.
Mary Lou McDonald was speaking as Westminster prepares to draft a budget for Stormont, following the two parties' failure to reach agreement before the deadline earlier this week.
Deputy McDonald insists that despite the impasse, they remain committed to striking a deal.
She said: "Why should people who live in the North of Ireland be placed at a disadvantage.
"We've been clear with the DUP, clear throughout, that we are here to do a deal, we want a deal, we want the institutions back up and running, we regard them as critically important
"But we also understand at this juncture, that we can't endlessly stagger from one crisis to another."