A senior New York Democrat predicted on Thursday that Joe Biden will not run for re-election in 2024, even as she apologised for saying that previously and also said she would support him if he did stand again.

Speaking to CNN, the congresswoman Carolyn Maloney said sorry for broaching the issue in a debate – but then said again she thought Biden would not run.

“Mr President, I apologise,” Maloney said, of her remark on Tuesday, when she said she did not “believe” Biden would seek a second term.

She added: “I want you to run.”

But then Maloney said: “I happen to think you won’t be running. But when you run, or if you run, I will be there 100%. You have deserved it. You are a great president, and thank you for everything you’ve done for my state, and all the states, and all the cities in America. Thank you, Mr President.”

Maloney, 76, and Biden, 79, are senior figures in a Democratic party some members say should be led by younger figures. Maloney’s primary opponent in New York, the House judiciary chair, Jerry Nadler, is 75.

Debating Maloney on Tuesday, Nadler said it was “too early to say” if Biden should run for re-election, and said “it doesn’t serve the purpose of the Democratic party” to debate the issue before the midterm elections in November.

Among mooted successors to Biden, the vice-president, Kamala Harris, is 57; Gavin Newsom, the governor of California, is 54; and Pete Buttigieg, the transportation secretary, is 40.

Biden was 78 when he was inaugurated in January 2021, the oldest president ever to take office. He will turn 82 shortly after the 2024 election. If he were to win that contest, he would be 86 by the end of his time in office.

Republicans claim Biden is too old to perform his duties properly. Democrats reject such claims.

Biden has repeatedly said he intends to run again. But polls consistently show majorities of Democrats and all voters saying he should not do so.

As one voter who spoke to The Focus Group with Sarah Longwell, a Bulwark podcast, put it recently: “It’s not the 82 that’s the problem. It’s the 86.”

In a recent Guardian column, Robert Reich, 76 and a former labor secretary in a Democratic administration, echoed such concerns.

“It’s not death that’s the worrying thing about a second Biden term,” Reich wrote. “It’s the dwindling capacities that go with ageing.

“… I think my generation – including Bill and Hillary Clinton, George W Bush, Donald Trump, Newt Gingrich, Clarence Thomas, Nancy Pelosi, Chuck Schumer and Biden – have fucked it up royally. The world will probably be better without us.

“Joe, please don’t run.”