The Conservatives were in disarray over their response to the energy crisis on Friday, with some Tory MPs backing Liz Truss showing signs of jitters over her refusal to spell out how she would help households.

The frontrunner to be prime minister in just over a week’s time said she would “ensure people get the support needed to get through these tough times” but had no new suggestions about how much or who would get assistance, with the average energy bill set to hit £3,549 from October.

One Conservative MP supporting Truss said they “wanted to see more” and hoped the Ofgem announcement would “sharpen thinking” in her camp, while expressing frustration that her campaign had not relentlessly focused on what to do about energy bills.

Another Tory MP who switched to Truss from another candidate said they felt “disappointed with the lack of focus on what matters to people” and acknowledged they had mostly backed her because she looked likely to win.

A third Truss supporter, Chris Skidmore, wrote an article saying the UK needed to be weaned off gas, despite his favoured candidate backing more North Sea gas and having called overnight for fracking to be exploited in the UK. “Anyone that suggests that our dependence on gas isn’t the problem, or that the solution is more gas, is gaslighting you,” he wrote for PoliticsHome.

After Ofgem’s announcement that the price cap would rise by 80% from October, Truss sent out a statement saying help would be forthcoming but gave no further details and her spokesperson said there would be “nothing more” for the rest of the day.

With little new from the Truss team, Boris Johnson set out his view that his successor would “plainly” have to act without capping prices for the very richest, while Nadhim Zahawi, the chancellor, said the reality was that “we should all look at our energy consumption”.

The chancellor assured the public that “more help is on its way” and he was “doing the work to make sure that will be in place throughout next year”.

Zahawi’s comments on cutting consumption put him at odds with the official government position set out by Kwasi Kwarteng, the business secretary and Truss’s likely next chancellor, that there is no need for people to reduce their energy use. No 10 has also said energy usage is a matter of “individual choice”.

Senior Tories are worried about the idea that asking people to use less energy could be viewed as a form of rationing, but officials have already drawn up plans for the next government to consider asking the public to voluntarily use less.

Despite the uncertainty over the plans of the next prime minister, Johnson told broadcasters on Friday that the cash “handouts” were “clearly going to be augmented, increased, by extra cash that the government is plainly going to be announcing in September”.

But he also said energy bills should not be subsidised for everyone. “What I don’t think we should be doing is capping things for absolutely everybody, the richest households in the country,” he said.

“This will go on for a few months and it will go on over the winter,” he added. “And it will be tough – and I’d be very clear about that – but in the end, we are also putting in the measures we need to ensure that we have the energy independence to get through this.”

The government was accused of being “missing in action” by the Labour leader, Keir Starmer.

He said: “You’ve got a prime minister who insisted on staying in office, recognises there’s a problem with energy prices, shrugs his shoulders and does nothing about it.

“You’ve got two leadership candidates who are fighting with each other about how appalling they have been in government, but neither has come up with any plan to deal with this problem. Unforgivable.”

Truss has repeatedly been criticised by her leadership rival, Rishi Sunak, for economic plans he claimed would worsen the pain felt by those already living in fuel poverty and others who will be pushed into it.

The former chancellor said pensioners and the most vulnerable would be supported if he became prime minister. “I want them to have certainty that extra help is coming,” he said.

Truss’s plans, which he said amounted to borrowing tens of billions of pounds for unfunded tax cuts, “don’t actually do anything to help the people most in need, risk making inflation worse and put our nation’s finances at risk as well”, he added.

Truss has limited her announcements about support to tax cuts, including reversing the national insurance rise and temporarily suspending green levies on energy bills.