Nadhim Zahawi has said he is “deeply concerned” people could freeze this winter if they are unable to afford energy bills.
But the chancellor was not able to guarantee no one would be cut off from their supply if they cannot pay.
It came after Liz Truss and Rishi Sunak made their final pitches to Tory members as the contest to replace Boris Johnson enters its final hours.
Truss said there would be no new taxes or energy rationing if she became prime minister.
While Sunak, who has repeatedly acknowledged he is the underdog, told the final leadership hustings “we shouldn’t rule anything out” on energy rationing.
In an interview with Sky News this morning, Zahawi was asked: “How concerned are you that people are going to freeze from the cold this winter because they can’t afford to put their energy up?”
The chancellor said: “I’m deeply concerned.”
Zahawi said the Treasury has been drawing up plans for what support can be given to people to help pay their bills and there is “nothing off the table” and he was looking at “all the options”.
But it will be up for the new PM to decide what action to take once they enter No.10.
Asked if he could guarantee people would not be cut off by energy suppliers if they could not afford their bills, he only went so far as to say: “No one should be cut off because they can’t afford their bills”.
Regulator Ofgem has confirmed an 80% rise in the energy price cap, which will mean the average household’s yearly bill will go from £1,971 to £3,549 from October.
Johnson, who will step down as PM on Tuesday, will deliver a speech on the country’s energy future later today.
Voting in the Tory leadership contest closes at 5pm on Friday and the winner will be announced on Monday.