DUP leader Arlene Foster has warned that the deal propping up British Prime Minister Theresa May's government would be at risk if the current Brexit deal is passed.
She told BBC Radio Ulster's Inside Politics: "If she is successful in parliament, and there is no evidence that she is going to be successful in parliament, then of course we will have to revisit the confidence and supply agreement.
"That agreement was about giving national stability, it was acting in the national interest and delivering on Brexit.
"If this is not going to deliver on Brexit then of course that brings us back to the situation of looking at the confidence and supply agreement, but we are not there yet and we are not going to jump ahead until we see what happens in parliament."
The DUP's Arlene Foster says time is being wasted by the promotion of the current Brexit deal. She says a new deal that everyone can sign up to is needed pic.twitter.com/9O2evcccJN— RTÉ News (@rtenews) November 23, 2018
The comments come as the UK Chancellor of the Exchequer Philip Hammond said the British government was examining ways of providing additional assurances to the DUP over the border backstop issue.
Mr Hammond said his government had a number of choices through the parliamentary process, including extending the implementation period, to avoid having to use the backstop.
He was speaking during a visit to Rowendale Integrated Primary School in Moira, Co Down.
Mr Hammond's visit comes as Spanish Prime Minister Pedro Sanchez has threatened to "veto Brexit" if it is not made clear that Madrid and London must resolve their differences over Gibraltar before any eventual future partnership is agreed.
Meanwhile, Prime Minister May travels to Brussels on Saturday to hold talks with European Commission president Jean-Claude Juncker ahead of the summit of EU leaders on Sunday which is expected to endorse the deal thrashed out between negotiators from the two sides.
Here, Tánaiste and Minister for Foreign Affairs Simon Coveney said he believed EU leaders would sign-off on the deal at Sunday’s summit and that a huge amount of work had been done in preparation for that, particularly in the past ten days.
A Government spokesman said Taoiseach Leo Varadkar spoke to European Commission President Jean-Claude Juncker today and told him the Dáil had approved the Withdrawal Agreement.
The spokesman said Mr Varadkar also told Mr Juncker that the "Irish Government was happy with the text of the political declaration on the future relationship".