James Brokenshire has said there is still time to save powersharing in Stormont.
The Northern Ireland Secretary of State said there are only a small number of differences between Sinn Fein and the Democratic Unionists, mainly around Irish language rights and culture.
Mr Brokenshire warned that Northern Ireland will begin to run out of money in the coming weeks and said it is highly unlikely a new executive could be formed in time to pass a budget by the end of November.
In a statement to the House of Commons, the Secretary of State said he was making plans to impose a budget to protect public services over the next year.
It will not make any spending decisions, he said.
"The Government's strong desire would be for a restored executive in Northern Ireland to take forward its own budget," Mr Brokenshire said.
"So this step is one that I am now taking with the utmost reluctance and only in the absence of any other option."
The Secretary of State said: "Even now - however unlikely this may be - should the parties demonstrate that an executive could be formed in the immediate future I would clearly wish to proceed instead with legislation to allow that to happen," he said.
Mr Brokenshire said a last-minute powersharing deal would be conditional on a budget being agreed and passed by the end of November.
He also said he will also reflect carefully on MLAs' salaries - £49,500 a year - which cannot be stalled or docked without primary legislation in Westminster.
Mr Brokenshire made his statement after Theresa May and Leo Varadkar spoke by phone and said it is still possible to revive powersharing.
The UK Prime Minister and the Taoiseach said they did not want a return to Northern Ireland being run by direct rule in the way it was before the Good Friday Agreement.
The Northern Ireland Secretary said: "I still hope that the parties can resolve their differences and that an executive can be formed.
"We will continue to work with them and support them in their efforts."
The DUP and Sinn Fein failed to meet Mr Brokenshire's original Monday deadline for a deal, after Stormont had been effectively in limbo since January.
Despite the deadlock, Mrs May is understood to remain committed to a £1 billion investment in Northern Ireland agreed as part of a voting pact between the Conservatives and the DUP at Westminster.
Mrs May's official spokesman said she and the Taoiseach had agreed in their phone conversation on the need for a "shared endeavour to see the restoration of devolved government" in Northern Ireland.
"They talked about the responsibility on parties to overcome their differences and the need for them to compromise on the outstanding issues for the benefit of all communities in Northern Ireland," said the spokesman.
Mrs May believes it is "not in anybody's interests" for there to be a return to direct rule, he added.
Mr Brokenshire also said the Conservatives remained committed to the £1 billion investment, agreed in return for DUP votes in Westminster.
"This Government, we stand by our commitments, and as a party we stand by the agreement that has been reached with the DUP. Nothing I have said today changes that," he said.
Mr Brokenshire said the Government was considering other interventions and other ways to help secure a deal between the DUP and Sinn Fein.
But he added: "I think it still remains possible but it is certainly difficult.
"We will continue to keep a range of options available to us to see how we can move this process forward."
He also said the crisis points between the parties are connected to Irish language rights and culture but also involve identity and respect.
Mr Brokenshire told MPs he believed the best way forward for dealing with legacy allegations against former servicemen and women for incidents during the Troubles had been agreed at previous talks.
He said: "I want to move forward with a consultation around the Stormont House Agreement which sets out new institutions, new bodies that are very firmly intended to be balanced, proportionate, transparent, fair and equitable and thereby ensuring that soldiers are not unfairly treated."
DUP MP Jeffrey Donaldson also insisted that the Armed Forces Covenant, which aims to give ex-servicemen and women some priority medical treatment, housing assistance and school places for children, was integral to a Stormont powersharing deal.
"There will be no outcome that will not see that Armed Forces Covenant providing for the servicemen and women and the veterans and their families from Northern Ireland who have served this country," he said.
"We look to the Government to support us in that outcome."
Mr Brokenshire said the Government wanted to see the covenant "touch" all parts of the UK.