Mr Mandelson told the Independent on Sunday the reform, which would involve keynote speeches moving to prime-time evening slots, was under review. The idea, which surfaced in the run-up to the general election last year, remained a possibility, Mr Mandelson said.
This year's gathering of MPs and party activists will have the usual format because plans for the event, to be held in Brighton, are well advanced.
However, some senior party figures believe the Labour party is failing to exploit the presentational opportunities offered by the sort of political conventions staged in the United States.
The issue is sensitive within the party because of the conference's traditional policy-making role. Although in recent years the leadership has become accustomed to winning all the key votes, critics have still used the event as a platform from which to oppose policy.
Last year Baroness (Barbara) Castle, the former Labour Cabinet minister, mounted a high- profile campaign at the conference to try to restore the link between pensions and earnings.
Traditionalists are already alarmed at plans to reform the role of the conference and Labour's National Executive Committee, and further reforms are likely to cause greater concern.
Modernisers such as Mr Mandelson see the potential of a revamp of the formula which would shift big speeches to early-evening slots.
In recent years the broadcasters have gradually scaled down their live coverage of party conferences because many journalists view them as too stage-managed.
Some Labour figures believe that, by building up several, nightly speeches, they could effectively force the television networks to devote live, prime- time coverage to parts of the conference they wish to highlight.
That is disputed by others in the party's media management team, who believe the BBC and ITV would be reluctant to carry speeches at length. They also stress the importance of getting the right presentation of speeches in news bulletins, rather than in live coverage.
In his interview with the Independent on Sunday, Mr Mandelson denied any difficulties with John Prescott, the deputy prime minister, who last week likened him to a crab.
However Mr Mandelson admitted that relations between the two men were strained in the late 1980s under the leadership of Neil Kinnock.
Mr Mandelson also admitted past difficulties in his relationship with the Chancellor, Gordon Brown, arising from the 1994 leadership election. Mr Mandelson's decision to back Tony Blair for the leadership, rather than Mr Brown, is said to have provoked a rift.
Mr Mandelson said any strains had been resolved, but added: "I wouldn't believe what you read in books and newspapers because it is laced with a lot of misinformation and the noise of axes grinding.
"It is no secret that Gordon was disappointed when he did not stand in the leadership in 1994 and some around him were looking for a scapegoat to blame. I was a convenient target."
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