Boris Johnson has doubled down on his insistence that it is for his successor to "make significant fiscal decisions" after talks with energy bosses ended with no new measures to ease the cost of living crisis.
Speaking after the meeting, the prime minister said he would continue to urge the energy sector to ease the financial pressures facing struggling families.
Mr Johnson has been under pressure to use his remaining time in office to come up with a new package of measures to deal with the rising cost of living.
He has been accused of going "missing" and running a "zombie government" as the country hurtles towards a recession, with energy bills forecast to top £4,200 by January.
On Monday he rejected calls from Gordon Brown to hold daily emergency COBRA meetings to stop people "going cold and hungry" this October, when the energy price cap rises.
The former Labour prime minister said fresh support can't wait until a new PM is chosen on 5 September.
However, Mr Johnson's spokesman said that "by convention it is not for this prime minister to make major fiscal interventions during this period".
In a tweet after today's meeting, Mr Johnson said he knows people are worried about the "difficult winter ahead".
He said there is already a package of support in place, including a £400 energy bill discount for all households.
The Treasury said that Chancellor Nadhim Zahawi and the energy firms agreed to "work closely" over the coming weeks to ensure that the public, including vulnerable customers, are supported in the face of rising costs.
Britain faces a national emergency with rising energy bills and a cost of living crisis.
But Labour accused the government of showing a lack of urgency and of being "missing in action".
"Families are worried about how they will pay their bills. But instead of showing leadership, the Conservatives are missing in action.
"The prime minister and chancellor have gone AWOL, whilst the candidates for the leadership have no substantive ideas about how to help working people meet the challenges they face.
"Labour will take the action that's needed to get us through this crisis, with real action to bring down energy bills for families, and build a stronger economy for our country."
Liberal Democrat leader Sir Ed Davey added: "It is appalling that the Conservatives still haven't announced any extra support for families and pensioners facing the hardest winter in decades.
"The cruellest element of this chaos is that those who could actually help, Truss and (Rishi) Sunak, are more interested in speaking to their party than taking the action our country needs."
Meanwhile, former leader of the Labour Party Jeremy Corbyn is among a group of MPs who have said Parliament should be recalled to discuss how to tackle the cost of living crisis.
Writing a letter to Boris Johnson, Keir Starmer and both the speakers of the House of Commons and House of Lords, the MPs say recent assessments of the rising cost of energy are "naturally causing fear and consternation for many people" and that Parliament should be recalled "in the public interest".
Other signatories include former shadow home secretary Diane Abbott, former shadow chancellor John McDonnell and former shadow business secretary Rebecca Long-Bailey.
Gordon Brown 'not leading Labour's policy'
The roundtable meeting comes as Labour prepares to announce its own package of measures to tackle the cost of living crisis.
Sir Keir Starmer will be visiting Edinburgh tomorrow, where he is expected to speak about some of the elements of the party's proposals to help people with rising energy bills, before a full announcement next week.
Labour has faced criticism for attacking Boris Johnson for going on holiday amid the worsening economic crisis, despite Sir Keir also being away himself.
Earlier on Sky News, a Labour frontbencher denied Gordon Brown was leading the party's policy in Sir Keir's absence after the ex-PM called for energy firms to be temporarily nationalised, in his third major intervention this week.
Shadow Justice Minister Steve Reed said Labour would be setting out a package of proposals "in the next few days".
Asked if Gordon Brown was "leading the charge of the Labour party", he said: "No, Labour is going to come up with a fully costed package of proposals for how we will help the British people. Next week is when we are going to bring that forward."
Labour has already called for ministers to scrap what they call a "loophole" in the windfall tax on oil and gas profits.
The government announced in May that it would be introducing a levy on the "extraordinary profits" of the oil and gas sector. This included a tax break which the government said was intended to encourage investment.
But Mr Reed said it was doing "nothing of the sort" as he called on the government to come up with solutions to the cost of living crisis now instead of watching the Tory leadership contenders "fight each other like rats in a sack".
Earlier this week, Lib Dem leader Ed Davey called for the rise in the energy price cap this October to be scrapped and for the cost to be covered through a windfall tax.
And today, Scottish First Minister Nicola Sturgeon also piled on the pressure as she said the energy price cap rise should not go ahead and accused the UK Government of being "missing in action" on the issue.