Chancellor Philip Hammond has failed to rule out offering the DUP more funding for Northern Ireland in a bid to win support of the party for Theresa May's Brexit deal.
Mr Hammond's comments come as speculation mounts that the UK government will have to offer fresh funding for Northern Ireland as the Prime Minister battles to secure support for the Brexit withdrawal agreement.
The Chancellor, speaking on the BBC's Andrew Marr Show, said: "Well the DUP, as you would have heard Nigel Dodds saying on Friday, is primarily concerned about the threat of divergence between the regime in Northern Ireland (NI) and the regime in Great Britain (GB).
"The DUP are passionate Unionists, I am a passionate unionist myself, and I regarded it as crucially important that we do not allow differences to grow up between NI and GB.
"We are looking for ways the government can reassure Northern Irish politicians about our clear intention to make sure there are no such differences as we go forward, if the backstop ever had to come into force."
Pushed on whether the government has offered more funding to Northern Ireland to the DUP during meetings with Nigel Dodds MP on Friday, Mr Hammond said: "This isn't about money, it is about political assurance. We are coming up to a spending review and we will have to look at all budgets, including devolved block grant budgets, in that spending review. Of course we will."
He added: "We have got an additional complexity in Northern Ireland. The House of Commons voted a budget through for NI last week and NI is in very difficult circumstances because the civil service has not been able to take quite difficult decisions that need taking.
"We hope that once we have got Brexit dealt with we will be able to resume power-sharing executive in NI and then of course we will have to look at the spending review in that context."
Asked if he would rule out providing extra funding to Northern Ireland in return for DUP MP's support, Mr Hammond said: "That is not where the discussion has been around."
Yesterday the DUP stressed extra cash for Northern Ireland is not forming part of the Brexit deal discussions.
The party stressed that the presence of the Chancellor at a meeting with the party on Friday did not mean that money was an issue.
A DUP spokesman said: "We are in discussions with the Government to ensure Northern Ireland is not separated out from the rest of the United Kingdom as we leave the European Union.
"Contrary to some reports we are not discussing cash. There are still issues to be addressed in our discussions."