The party's Plant commission is due to report on the issue in the spring, but the damage some believe Labour suffered at the general election from raising it has hardened opposition.
However, John Kemp, from Dundee West, said Labour had obtained a working majority only twice in 90 years of elections. 'The simple fact is that the present electoral system has for almost a century marginalised the Labour Party. We can no longer continue in support of an unfair electoral system on the grounds that we might one day benefit from that unfairness.'
Jeff Rooker, chairman of the Labour Campaign for Electoral Reform and a member of Plant, said Labour had won more votes last April in 16 shire counties where no Labour MP was elected than it had in 11 cities which returned 54 Labour MPs. And that, he said, was before Boundary Commission changes would give the Conservatives another 12 to 20 seats next time. The party had to give those Labour voters a voice.
Jean Lord, from Littleborough and Saddleworth, said: 'I didn't join the Labour Party to be fair to Liberals. I joined to get a Labour government.' Proportional representation would have given Labour fewer seats last April and control of fewer councils.
Margaret Beckett, the party's deputy leader, hinted at her own strong personal opposition to changing the voting system by saying the Plant commission had already made clear that there was 'no one perfect, correct, theoretically supreme voting system'.
Earlier, Tony Blair, shadow Home Secretary, had told the conference: 'It is now time that we consider the incorporation into British law of the European Convention on Human Rights as the first step to a new Bill of Rights for Britain.'
Mr Blair's backing for the concept of entrenched individual rights departs from traditional Labour suspicion of a Bill of Rights because of the danger that a broadly worded document would be open to manipulation by judges.
Mrs Beckett said the reform was still subject to debate within the party and the conference agreed not to vote on the issue.