Outgoing deputy prime minister John Prescott says his successor should focus on boosting party membership, rather than a big government job.
He spoke hours before Harriet Harman won the six-way race to follow him as Labour's deputy leader.
Mr Prescott, who is recovering from pneumonia, said they had to concentrate on "bringing back enthusiasm".
He also told the BBC he opposed any Lib Dem being in the Cabinet, saying he had always been "Labour, old Labour".
Although it was not up to him what Gordon Brown did in the new era, he said that he had told Tony Blair in the past that if the then Lib Dem leader Paddy Ashdown had been given a place in Cabinet, he would have walked out.
Mr Prescott has served as both deputy leader and deputy prime minister, but it is not known if his successor will do so. He also ran the "super department" covering environment, transport and the regions.
'Eye off the ball'
In an interview with BBC One's Sunday AM programme, he said candidates should not be concerned about who should be deputy prime minister.
"That is the prime minister's job, this is about party, it is an important party job and I think that they've all recognised that is the case," he said.
"I think we took our eye off the ball to a certain extent about the politics of organisation being as important as politics of ideas and policy," he said.
"Let us get on with the organisation, strengthening the party, bringing back enthusiasm into it, these are essential to win the next election."
Gordon Brown is the sole contender for the leadership post, but six MPs have taken part in a seven-week contest for the deputy post.
'Discipline in government'
The candidates were International Development Secretary Hilary Benn, Labour chairwoman Hazel Blears, backbencher Jon Cruddas, Northern Ireland Secretary Peter Hain, Justice minister Harriet Harman and Education Secretary Alan Johnson.
Harriet Harman, bottom centre, won the six way deputy leadership contest
Mr Prescott played down claims the contest had been divisive, given that some candidates - five of whom are senior members of the government - had appeared to criticise government policies.
"I do notice when I hear some of these comments I didn't hear them in the Cabinet at the time but these are elections, these are campaigns, they are pressured by all sorts of people, and I think people understand that. They are setting out their stalls as they see it."
In an interview with BBC One's Politics Show, Mr Brown said members of his government would have to support "the manifesto of our party" adding "there will have to be discipline in the government that I lead".
Mr Prescott, who was taken ill on a train three weeks ago with pneumonia and admitted to a high-dependency unit in hospital, admitted it had been a "scary" experience and said he was "well" but still under doctor's orders.
Asked about his future plans and a possible peerage, Mr Prescott said he would tell members of his constituency first of his plans, but for the time being he still had work to do on the abolition of slavery commemorations.
He said he wanted to take part in the next general election campaign and any discussion about stepping down was "two or three years away".