Tony Blair has said Labour must focus on the public's concerns - rather than continue the in-fighting which had led the party "to go AWOL" in recent weeks.
On BBC One's Sunday AM he refused to comment on who might succeed him when he steps down in the next year.
The leadership question "will deal with itself in due course", the PM said.
He said Labour's conference this week in Manchester should concentrate on the issues - such as immigration and terror - that the public worried about.
LABOUR WEEK AHEAD
SUNDAY: Conference gathers, with round of media interviews including Blair on Sunday AM, Brown on Politics Show
MONDAY: Brown's keynote speech. Also taking to the platform are Alistair Darling and John Hutton
TUESDAY: Blair's keynote speech. Also taking to the platform are Margaret Beckett and Ruth Kelly.
WEDNESDAY: Alan Johnson, David Miliband, Patricia Hewitt all take to the platform
THURSDAY: John Reid, Peter Hain and John Prescott all take to the stage.
Mr Blair said he did not want to "play the game" as he was asked repeatedly to comment on issues to do with who might replace him.
He refused to confirm or deny a News of the World report saying he was not going to endorse Gordon Brown.
Nor would he say whether he still thought that Mr Brown would make a "brilliant prime minister".
Mr Blair said he was not going to "resile" (draw back) from anything he had said before about the chancellor and said their's had been a "remarkably successful" partnership "for the party and the country".
He said: "Gordon has been a fantastic chancellor, he's been a great servant of the country and the party... .but this week I am talking to the public about the public's concerns.
"And that's the agreement we made at Cabinet, and that's what we are going to do. And both of us realise - and we were talking about this yesterday - that the most important thing is that this week we set out an agenda for the future."
Mr Blair said earlier this month this would be his last annual Labour conference as leader - an announcement which came during a period of in-fighting over his departure date.
Mr Brown is the favourite to succeed Mr Blair, but there have been tensions after the chancellor's supporters were blamed for trying to force Mr Blair out earlier than he might have planned.
The run-up to conference has seen widespread jockeying for position by Cabinet ministers who might either run against Mr Brown or who might want to run to replace John Prescott as deputy prime minister.
Mr Blair warned Labour: "The danger for us is very, very simple. This is the problem with the last few weeks.
"For the first time since I became leader, the Labour Party went AWOL (absent without leave) from the British public, it looked in on itself, it started all the in-fighting and the rest of it.
"The public out there are angry about that. They don't want to see their Government do that. They want us to govern."
Mr Blair said he was concentrating on preparing for his big speech on Tuesday - and on running the country - rather than wanting to talk about the leadership.
He said that at the right time "I will answer all these questions fully and in detail".
Mr Blair said it felt "strange" knowing it would be his final conference as leader - and said he did not know whether he would go to next year's Labour conference.
He told Sunday AM immigration, terrorism and law and order would form the centrepiece of this autumn's Queen's Speech.
He said he did not agree with the view - reportedly supported by US intelligence - that Iraq had increased the threat of terrorism.
He said: "Part of the biggest problem we have is in believing that we started this thing... 9/11... happened before Iraq or Afghanistan.
"The roots of this movement, founded on a warped and perverted view of Islam... go back decades, and it's going take us a long time to root it out."
He said Mr Brown's suggestion, in BBC One's Politics Show, of a new independent structure at the helm of the NHS should be debated.
But the most important thing is to keep the reform programme going," added Mr Blair.
The opening of the conference also saw ministers Hilary Benn, Peter Hain and Harriet Harman call for more debate about whether the Trident nuclear missile system should be replaced - as Mr Brown has signalled.
But one delegate complained that concerns on the issue were being gagged after 17 motions on the issue submitted by local Labour parties were ruled inadmissible on technical grounds by the conference arrangements committee.
Both Sunday AM and Politics Show can be watched after transmission at their websites (see links further up the right hand side of this page). There is also a Panorama special on Gordon Brown on BBC One on Sunday at 2215 BST.