Conventional political wisdom has presumed merging Sydney's councils is a politically charged policy, particularly as mayors gear up campaigns against amalgamations. But a new Fairfax/Ipsos poll of 1000 NSW voters may suggest otherwise.

Sydney voters remain divided on the issue: 48 per agree with the state government that there are too many councils, while 45 per cent oppose a reduction.

But only one per cent of voters said the issue would determine which party they supported.

But the state government could be on more dangerous ground politically after it left open the possibility of forced mergers, if councils refuse cash incentives to merge voluntarily: 54 per cent of voters opposed forced mergers and 40 per cent supported them.

Roberta Ryan, the head of the UTS centre for local government, said she expected the merger issue to grow in prominence as next year's March election drew closer. "Discussion in the community is already picking up," she said.

But Ms Ryan said the level of support for compulsory mergers was surprisingly high and showed the government's rhetoric appeared to be working. "Forced anything is a hard sell," she said.

But even one of the merger plan's leading opponents now seems to accept it as politically inevitable.

Canterbury Mayor Brian Robson said he had been holding merger talks with neighbouring Bankstown and St George councils. Mr Robson leads the Metropolitan Mayors' Forum, a grouping of about 10 councils that has strongly opposed the amalgamation plans.

Councils have until June to present the government with merger plans or demonstrate their fitness to continue running independently.

"We're being set up to fail in one way or another," Cr Robson said. "They'll just [force mergers] anyway after the elections".

Other councils are taking up the fight.

North Sydney has tried to combine a plebiscite of its residents' views of amalgamation with the March state election ballot.

Holroyd and Fairfield mayors have confirmed they are investigating a similar poll, which would put the state government in a difficult position if voters reject mergers.

But the NSW Electoral Commission is refusing to run the poll on the same day as the state election, worrying it will be costly and confuse voters. North Sydney is now investigating the legality of having another body conduct it.