Plans to reform the voting system, put forward by health secretary Alan Johnson, are reported to be gaining support.
Johnson wrote in Monday's Times that the public should be asked whether they want a more proportional voting system, rather than the current 'first past the post' system.
The cabinet minister said that voters should be given a choice between 'alternative vote plus' and the present system in a referendum.
"This is a genuinely radical alternative that only Labour in government can facilitate," he wrote. "We need to overhaul the engine, not just clean the upholstery."
The Times reported that up to 100 MPs have expressed interest in electoral reform and Johnson's plans could be included in the next Labour manifesto.
Johnson, meanwhile, has denied that his calls for a referendum on voting policy were part of a bid to replace Gordon Brown as leader.
Dods Parliamentary Communications Ltd