Some newly merged councils are investing in new brands.

Tender documents show the new Canterbury-Bankstown council has allocated $375,000 to "develop, create and activate" a new branding strategy.

Redfern agency The Frost Collective will undertake a "brand audit" and develop new "brand architecture".

But one expert queries whether the spending is necessary. Another says re-branding is only the first in a string of larger fiscal challenges for councils absorbing new territory, which could eat into the financial benefits of mergers.

"That [$400,000] is an awful lot to invest in a new image when you're not really changing what you do but consolidating it," said Martin Bass, an independent consultant who specialises in local government. "These are areas facing some pretty serious social problems.

"It's widely known that [senior council staff's] email in-boxes are overflowing with pitches from consultants."

Mr Bass suggested consultants are driven by a search for some of the $10 million plus in incentives handed to merging councils by the state government.

A Canterbury-Bankstown spokesman said the council had grown to 350,000 residents and needed to distinguish itself as a new part of Sydney.

"This is not just about developing a new logo, it's about establishing an identity and 'place brand' owned and promoted by the city and its people," the spokesman said.

Other councils are expected to follow suit: Cumberland Council and the likely-merging Eastern Beaches council and some rural councils have already brought in ad agencies but have not confirmed the cost.

Dr Joseph Drew, from the University of Technology Sydney's Institute of Public Policy and Governance, says the re-branding splurge presages a much larger challenge for councils.

Councils absorbing new territory will need to standardise employment awards and decades of idiosyncratic filing and computer systems; costs likely to dwarf any re-branding.

But the biggest cost will be equalising services residents receive, Dr Drew said, and international research suggests that councils' costs almost never drop in this process.

In some newly-merged regional councils residents on one side have had fortnightly rubbish pick-ups and weekly on the other; pools on one side of new boundaries may be heated but not on the other.

But he says many councils find themselves in a bind because the Baird government has effectively frozen rate rises until after the next state election.

"It's all these expenses at once and no one ever modelled them at all," he said. "It's a little timebomb ticking away".

Perhaps unsurprisingly, the council absorbing the former political home of Salim Mehajer, Cumberland, was one of the first to re-brand, immediately after merging with a new logo, a mix of blue, green and grey blocks.

On some council offices, the council's new name is accompanied by an old slogan: "Home of the 2000 Olympics".

Some residents have noticed.

"We just thought 'Ugh'," said resident Cheryl Lloyd.

The council is now bringing in professionals.