Liz Truss has said soaring energy bills are a “price worth paying” in order to stand up against Vladimir Putin’s invasion of Ukraine.
Speaking to reporters in New York, the prime minister said she would not be telling people to ration their energy use this winter.
Truss added the UK “cannot jeopardise our security for the sake of cheap energy”.
The government has already announced plans to freeze household energy bills from October 1.
Under the scheme, bills for the average home will not increase past £2,500 for two years, saving typical households around £1,000.
An “equivalent” scheme to help businesses cope with skyrocketing bills is due to be announced this week.
But unlike the support for households, it is only expected to be in place for six months.
Downing Street has also admitted help for businesses might not arrive until November, with support having to be backdated to cover October’s bills.
The PM is in the United States for a United Nations summit where she is due to meet world leaders, including US president Joe Biden.
Truss said higher energy costs were worthwhile if it meant defeating Putin.
“The point I’m that I’m making is that it’s a price worth paying for Britain, because our long-term security is paramount,” Truss said.
“But what I don’t want to happen is that to be passed on to bill-payers who beyond that energy guarantee that I’ve outlined because I don’t think that’s right.”
She added: “We are not talking about rationing of energy.
“Of course, I always support energy efficiency measures like home insulation, that makes sense, and energy prices are higher than they were.
“There is a strong incentive for businesses and households to invest in energy efficiency, but we do have reliable supplies of energy but ultimately everyone makes their own decisions about how they decide to do those things.”
On her flight to the UN, Truss also admitted negotiations for a post-Brexit free trade deal with the US will not restart for years.