The state government has spent nearly $6 million in the past six months on advertising and consultants for its controversial plans to merge the state's councils, documents released under freedom-of-information laws show.

But some councils are also spending big in an attempt to influence the state government's plans to merge many NSW councils unveiled last year.

The government has spent little more than $3.5 million on consultants. The balance has gone on advertising.

Top ad firm Saatchi & Saatchi billed taxpayers about $300,000 to develop an advertising strategy for selling council mergers, with a further $1.8 million on advertising spending.

"There's been no spontaneous rallies in the street endorsing [council mergers]," said NSW Labor's local government spokesman, Peter Primrose, in an allusion to protests against government plans late last year. "Advertising an in-coming policy is one thing, but using [public money] to convince people is something else."

But local councils have been busy too.

Many commissioned a flurry of consultants' reports and public phone polls often registering immense support for their own positions in the lead-up to mergers.

Botany Council will spend about $100,000 on a plebiscite gauging voters' support for plans to merge it with neighbouring Rockdale.

Ryde council is preparing another $20,000 phone poll of residents' views on plans to merge it with Lane Cove and Hunter's Hill councils.

A spokesman for the Local Government Minister, Paul Toole, defended the government's spending, saying reform of this magnitude required research and advising communities of governance changes.

"Spending hundreds of thousands of dollars campaigning against a reform that will benefit local communities is clearly not a good use [...of] ratepayers' money," the spokesman said. "With turn-outs traditionally only as high as 30 per cent [plebiscites] do not guarantee a balanced or genuine insight into the opinions of a local community."

Community opposition has led some coalition MPs, such as Kiama's Gareth Ward, to speak out against merger plans.

Labor has criticised the state government for its spending on reports because it argues it has ignored some of their conclusions.

The Independent Pricing and Regulatory Tribunal charged $1.6 million to review proposals to merge or stand alone from the state's 150 councils, a report it delivered in October.

Some councils found by IPART to have been financially unfit to stand alone, such as Liverpool, have been allowed to continue without any merger.

The news comes as public meetings on mergers are slated to start this week, with many in local government concerned about the way in which they have been organised.

Inquiry meetings will be held at Manly, Hunters Hill, Shellharbour, Ashfield, Sans Souci, Mona Vale, North Sydney, Deniliquin and Bankstown on Tuesday, with other meetings to be held across the state in the next fortnight.

Keith Rhoades, the president of Local Government NSW, the representative body for the sector, said he had received a number of complaints from mayors about the meetings.

One complaint, Mr Rhoades said, was about the timing of the meetings, which in some instances made it difficult for people to attend after work. There had also been complaints about inadequate venues, and the fact that anyone wishing to speak at the meetings will have to have pre-registered.