Former Cabinet minister Ed Balls is sounding out colleagues over a possible bid for the Labour Party leadership.
Mr Balls said he would decide "in due course" whether to stand against the only currently declared candidate David Miliband.
Former foreign secretary Mr Miliband said he hoped as many candidates as possible would stand and indicated his rivals could include his "immensely talented" younger brother Ed.
Mr Balls said the Labour Party wanted a "proper debate" about the lessons which needed to be learned after the election, the former schools secretary said: "I'm obviously talking to people but I don't want to jump to any quick conclusions."
Mr Balls, a close ally of former prime minister Gordon Brown, faced a tough fight to win his Morley and Outwood seat in West Yorkshire with a majority of just over 1,000 at last week's general election.
He told a news channel: "I think the pretty strong message from the Parliamentary Labour Party was they wanted to make sure that we talk about what's happened in the election last week in a constituency like mine, where it was closely won, but there are some real issues for us to look at.
"There's got to be a proper debate, people want a proper debate and I'm going to take that very seriously. I'm talking to people in the parliamentary party and in the wider country too and I will decide in due course."
If he does run he will be able to count on the support of Mr Brown's former spin doctor Michael Dugher, who was last week elected as MP for Barnsley East. He told a radio programme: "I will support Ed Balls. He's not said whether he is prepared to stand yet, I hope he does. I think, like David Miliband, Ed is a great talent in the Labour Party. We are lucky to have David Miliband and Ed Balls and indeed others."
Former justice secretary Jack Straw, seen as an outside contender to replace Mr Brown, said he would not be running in the leadership contest, other possible contenders for the leadership include former health secretary Andy Burnham and popular backbencher Jon Cruddas.
Candidates will have to appeal to all sections of Labour under the party's electoral college system for finding a new leader, which sees three "blocs" - the parliamentary party, wider membership and affiliated groups including the unions - having a say.
