The Liberal Democrats say they have held talks with Downing Street about introducing proportional representation for general elections.
Lib Dem leader Charles Kennedy
Tony Blair was thought to have gone cool on electoral reform after 1997.
In Labour's 2001 manifesto a review of the voting system was promised and Lib Dem leader Charles Kennedy now wants Labour to stand by that pledge.
Mr Kennedy told the Independent: "We had some informal discussions. It's on their agenda."
The Lib Dems want the current first-past-the-post voting system used for Westminster elections to be dropped in favour of a proportional representation system.
It has been a long-standing policy from the UK's third biggest party, which currently has less than 10% of MPs despite getting nearly 20% of the vote.
In recent years such a system has been used for elections to the Scottish Parliament, Welsh Assembly and European Parliament.
Backers believe that it might boost turn-out at elections if people knew that their vote counted.
A Lib Dem spokeswoman said: "There have been informal discussions between the Liberal Democrat leadership and Downing Street on PR.
Turnout in General Elections
1974 (Feb): 78.7%
1974 (Oct): 72.8%
"We have proposed the Government should review the operation of PR in Scotland, Wales and the European elections after June 10 (the date of Euro elections in 2004) as a basis for what to do about Westminster elections.
"That was also a Labour Party manifesto commitment and we are keen to hold them to it. But the ball is now in the Prime Minister's court."
The issue was discussed behind the scenes between former Lib Dem leader Paddy Ashdown and Tony Blair before the 1997 election - but ruled out after Labour won by a landslide.
News of the renewed talks - at the Lib Dems' request - will alarm those senior Labour MPs who had assumed the issue was now off the agenda.