Following David Miliband's call for change in the Labour Party, Peter Mandelson has joined the speculation over Gordon Brown's future.
The EU trade commissioner insisted it was not surprising that Foreign Secretary Mr Miliband had made "his own contribution" about how the party should move forward.
"Of course people will be asking themselves how we can set a new sense of purpose and direction for the Government," he told BBC Radio 4's Today programme.
"Frankly, if he and everyone else just packed their bags and went off on holiday without a thought to the flux they are in, then I think frankly I would find that rather more surprising."
Mr Mandelson said the Government had "lots of talent", and it would be "strange" if there were not other senior figures who were qualified to be prime minister.
Mr Miliband published an article saying the ruling Labour Party must change and defy the odds to win the next election.
Brown's popularity has been hammered by a slowing economy and a string of local electoral defeats, and some party members have called for him to step down.
"The odds are against us, no question. But I believe we can still win the next election," Miliband, a rising Labour star, wrote in The Guardian.
Miliband is likely to challenge Brown in any future Labour leadership contest. His article did not criticise Brown but also did not back him. Miliband did not even mention Brown by name, and the story was dotted with calls for "change" and "modernisation."
Miliband said Labour had won three national elections since 1997 "by offering real change, not just in policy but in the way we do politics."
"We must do so again. So let's stop feeling sorry for ourselves, enjoy a break, and then find the confidence to make our case afresh," he wrote.