The DUP and Sinn Féin have clashed over the cost-of-living crisis as a major gas supplier in Northern Ireland announced its biggest price hike in over a decade.
Sinn Féin criticised the DUP for collapsing the Stormont Executive, saying it means Finance Minister Conor Murphy has £300million that "cannot be spent" to help struggling families.
DUP leader Sir Jeffrey Donaldson disputed Sinn Féin arguments that all options to secure a three-year budget had been legally exhausted and urged rivals to "stop playing politics".
Read more: SSE Airtricity announce highest gas price rise in over 10 years in Northern Ireland
He said he wants to see a fully functioning Executive at Stormont, but contended this is not realistic with restrictions placed on Northern Ireland by Brexit's Protocol.
It came as SSE Airtricity announced gas prices in its network will increase by 39% from April 1 amid rising wholesale costs.
The move will affect around 186,000 customers in Northern Ireland and has been described as the biggest rise in gas prices in the SSE Airtricity network since May 2011.
It will mean the annual gas bill of a typical household with a credit meter will go up by about £244, the Consumer Council said.
The advice body said Russia's invasion of Ukraine is likely to increase the pressure on gas and oil supply, which in turn will further push up costs.
Stormont party leaders are due to hold a meeting next week to discuss how to resolve funding issues and ease cost-of-living pressures.
The DUP pulled Paul Givan out of the First Minister post last month in protest against the Protocol, forcing the resignation of Sinn Fein's Michelle O'Neill as Deputy First Minister.
Other ministers remain in place but they can only make some limited decisions as the full five-party Executive cannot meet.
Sinn Féin leader Mary Lou McDonald said the DUP had "robbed us of that opportunity" to protect families and workers from the rising cost of living.
She said: "It has to be said that the DUP walking away from the Executive, scuppering the three-year budget, has added to the huge difficulties that we face.
"It has meant that Conor Murphy as Minister of Finance has £300million that now cannot be spent by the Executive."
Sir Jeffrey wrote to Stormont's main party leaders ahead of their scheduled meeting next week seeking to agree ways to find funding to help with energy costs and to approve a draft budget without an Executive.
Sinn Féin vice-president Michelle O'Neill said the Finance Minister had "exhausted legally all options that are open to him" to agree a three-year budget.
Ms McDonald and Ms O'Neill urged the UK government to intervene over the rising cost of living in the absence of a fully functioning Executive.
Sir Jeffrey Donaldson said he would "not take no as an answer" from Sinn Fein over the Stormont budget.
He told reporters in Bessbrook, Co Armagh, that he does not accept the contention that the Finance Minister had exhausted all legal options.
"Sinn Féin were saying that about a lot of things, they told us there couldn't be vital legislation put through the Assembly - it is being put through the Assembly," he said.
"They told us that there wouldn't be an apology to the victims of historical institutional abuse - that apology will take place next Friday.
"They told us that it wouldn't be possible to provide funding for sub-regional stadia for our football clubs in Northern Ireland, yet their minister is now bringing forward a funding package for football stadiums.
"So if they can do it for football stadiums, why can't Sinn Féin do this for households right across all of Northern Ireland, who today are struggling with rising energy costs and with rising food prices in the shops?
"So I'm sorry, I don't accept this. I believe that it is important, as I have called for the party leaders to come together to sit down to look at the options that we have, and see how we take this forward.
"I'm not going to take no for an answer from Sinn Féin."
Alliance Party leader Naomi Long said the "law is clear" that the budget "cannot be done without an Executive".
The Justice Minister tweeted that the "solution" is Sir Jeffrey "can nominate a First Minister".
Meanwhile, SDLP deputy leader Nichola Mallon has written to Communities Minister Deirdre Hargey proposing that a £200 energy payment support scheme is extended to all bill payers in Northern Ireland.
The scheme, which will make one-off £200 payments to help people on some benefits, launches on Thursday.
Ms Mallon said: "There is an urgent need to act now to support all families who are in severe financial difficulty, those in receipt of social security and those on low incomes who are not.
"We have an obligation to pursue every path available to support people who are being hit by this crisis. In the absence of an Executive, it is clearly more difficult to take the action necessary to safeguard people and families in need."
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