Mr Slater, who has run Scratchley's restaurant on the harbour for 32 years, said he had lost $60,000 and his staff had missed out on $20,000 in wages during each of the previous race weeks.

City of Newcastle says it will assess whether to extend the race for another five years after its five-year contract with Supercars expires in March.

Mr Slater said he supported fans' right to enjoy the race, but the 10-week bump-in and bump-out period for installing track infrastructure made it a financial burden on most businesses.

He said he admired the motor racing organisation's ability to "extract every dollar and keep it for themselves".

"They're like a vacuum cleaner. They hoover up every dollar available."

The council last month released the results of an economic analysis of the race by global accountancy firm Ernst & Young which estimated the Newcastle 500 delivered an average $16.7 million in direct benefits and another $20 million in indirect spending and returned $22.60 to the local economy for every dollar invested.

E&Y also estimated the event generated an extra 149 jobs, both directly and indirectly, for the city each year.

Mr Slater said he could not see how the report had come to these conclusions.

"A couple of hotels are putting up their prices fivefold, but who else is doing that?" he said.

"I would like to see the true figures. There's no one we can find like that."

He said Supercars imported its own food suppliers and staff, leaving little benefit for local traders or workers.

He predicted the race would be slightly less disruptive to businesses next year in its new March timeslot.

Greens councillor John Mackenzie last month slammed the E&Y report as a "betrayal" of local businesses which ignored the race's costs.

"There has not been the slightest attempt of this council to understand the impact of the race on the viability of business in Newcastle East, let alone lift a finger to compensate them in any way for these costs," he said.

Meanwhile, Newcastle East Residents Group has hit another hurdle in its attempts to force City of Newcastle to release Supercars documents.

NERG made a freedom-of-information request to the council in 2018 for documents detailing the city's dealings with Supercars.

The council refused, and the residents appealed to the NSW Civil and Administrative Tribunal.

The tribunal granted NERG access to most of the documents, but the council appealed. On the eve of that appeal, the council handed NERG most of the documents.

Three years later, the council is holding out on a section of a "letter of commitment" from Destination NSW to City of Newcastle chief executive officer Jeremy Bath which the residents believe could contain important information about the contractual relationship between the organisations.

Mr Bath said in a letter to NERG president Joan Browning last month that the council would not release the redacted sections of the letter and disputed NERG's claim that the redactions were inconsistent with the NCAT appeal panel's 2018 ruling.

NERG representative Christine Everingham said the saga was an "example of how difficult it has been to get any information about this event from either Destination NSW or CN".

"Why should we even have to use the expensive and time-consuming GIPA process, and appeal after appeal, only to have the council say they are not prepared to release this information," she said.

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