DUP deputy leader Nigel Dodds has said Sinn Fein must get back to power-sharing at Stormont or accept the introduction of direct rule from Westminster.
During Prime Ministers Questions in the House of Commons, Mr Dodds pressed Prime Minister Theresa May on the need for Ministerial decision making for Northern Ireland.
Following the outcome of Monday's ruling in Belfast High Court, when a judge blocked a decision by a senior civil servant to approve a huge waste incinerator plant, the civil service said their ability to make decisions for Northern Ireland could be affected.
It emerged on Wednesday that the Northern Ireland Civil Service will appeal the decision, but have said they will use the court ruling as a guideline in the meantime.
Senior civil servants have been taking the majority of decisions within departments since Stormont collapsed 16 months.
While the UK government has stepped in on occasion to make significant cross-governmental decisions, such as setting a budget and enabling the collecting of rates, the civil service has effectively been in charge, as Stormont exists in a limbo between devolution and direct rule.
Numerous attempts by the DUP and Sinn Fein to restore power-sharing have failed with the most recent attempt at an agreement collapsing on Valentine's Day over the Irish language, hours after it looked like a deal had been secured.
Speaking in the Commons on Wednesday the Prime Minister told Mr Dodds that she wanted to see Ministers in Northern Ireland making decisions, but that it depending on an agreement among the political parties.
“Having no functioning Ministers continues to cause havoc for people living here. Civil servants are trying to run Northern Ireland but in many cases big decisions and reforms are being left in limbo," Mr Dodds said.
"Whilst the Prime Minister reiterated her desire to see a functioning Executive, Sinn Fein continues to block progress. Four out of the five main parties would fully restore the Executive today. Sinn Fein have no interest and have checked out of decision-making.
"It is welcome that the Government will continue to work with all parties to see Stormont up and running but the ball is firmly in Sinn Fein’s court."
Mr Dodds said that the recent court ruling hastened the need for a solution to be found.
"We have been reminded again this week that Northern Ireland cannot continue to be run by civil servants. It’s time Sinn Fein for to face up to the reality. They stand alone. They can’t play games with people’s lives. Northern Ireland needs proper governance," the North Belfast MP said.
"Sinn Fein may not like Ministerial decisions being made in London but if they continue to block devolution then there are very few alternatives.”
Rejecting Mr Dodd's claims a Sinn Fein spokesperson said that the DUP's denial of rights to citizens was stopping power-sharing from resuming.
“The reason the power-sharing institutions are not in place is because the DUP reneged on the draft agreement in February," the spokesperson said.
“If Nigel Dodds and the DUP are now prepared to end their blockage on genuine power-sharing and rights for all citizens then Sinn Fein would welcome that.
“If they are not, then the onus is on the two governments to pave the way for a return to the institutions by convening the British Irish Intergovernmental Conference to resolve the issues at the heart of the DUP’s denial of rights to citizens.”