The energy price cap will rise to £3,549 from October as Britons face a cost of living crisis.
Money Saving Expert chief Martin Lewis has described the situation as a “catastrophe” while shadow chancellor Rachel Reeves said the government must do more.
She tweeted: “We cannot wait any longer to act. This is a national emergency. The Tories must freeze energy bills now so households don’t pay a penny more in winter.”
Below we outline the candidates proposals:
What Rishi Sunak has proposed
Former chancellor Mr Sunak is currently the rank outsider to succeed Boris Johnson but has a headline policy of temporarily scrapping VAT on energy bills in a bid to save families around £160 a year. He told the Times that he would be prepared to find £10billion by pausing or cancelling some government programmes to foot the bill of helping the poorest. He has said further temporary borrowing would be a “last resort”.
He tweeted on Friday: “As Chancellor, I put in place a significant package of support, but today we can see the situation has deteriorated so as Prime Minister I would go further.
“My plans will support people with the cost of living challenges and grip inflation.”
What Liz Truss has proposed
Ms Truss has promised an emergency budget in which she will announce tax cuts and reverse the planned 1.25 per cent increase in national insurance contributions. She has also pledged to relax restrictions on fracking to boost energy production in the UK and reduce the reliance on Russia - which has dogged the EU economy.
In a debate on Talk TV on Thursday, Ms Truss said soaring energy bills were a “massive issue” but the solution should not be to “just bung more money into the system”. She has also pledged to abolish green levies.
She added: “What we need is to fix the supply of energy. If people think this problem is going to be over in six months they’re not right.”
The Times has reported that Ms Truss is already holding talks with Kwasi Kwarteng, the business secretary and her rumoured next chancellor.