Cabinet minister David Lidington has denied the DUP's continued opposition to Theresa May's withdrawal agreement has "fatally undermined" the confidence and supply deal the party has with the government.
As support for Theresa May's withdrawal agreement grows and ahead of yet another crucial vote in the Commons in a special Friday Commons sitting pressure has been growing on the DUP to support the deal, something it says it can't do.
The Conservatives and the DUP have in place a confidence and supply agreement in order to allow Theresa May to operate a minority government.
In it the DUP pledged to support the government on passing legislation on leaving the EU.
Asked if the DUP's continued refusal to support the withdrawal agreement undermined the confidence and supply deal, Mr Lidington said it did not.
The minister - who chairs the co-ordination committee set up by the deal - added: "It was very disappointing what the DUP said last night about the EU exit deal.
"They coupled that with saying there has been constructive discussions on domestic policies. So ironically there has been some very cordial negotiations, conversations with them in the last few weeks about other matters and they haven't, at least not yet been persuaded to, back the EU deal."
In a business conference address in London on Thursday the defacto deputy prime minister raised concern about what a no-deal Brexit might mean for the integrity of the UK.
He said more moderate nationalists who had been content to live in Northern Ireland had grown "unsettled" due to both the referendum result and the continued absence of local government.
"I do always bear in mind that Northern Ireland's place in union rests on consent," he added.
"We need to make sure we give everybody confidence that the union is going to work for everyone."