Opponents of Melbourne's Formula 1 Grand Prix say the organisers of the race are vulnerable to a court challenge over their claims about the financial benefits of the event.

The Save Albert Park group says a leading Melbourne QC has provided legal advice that it has grounds to sue the Australian Grand Prix Corporation and Victorian Government for alleged misleading and deceptive conduct under competition and consumer laws.

The group has not committed to pursuing the case, but spokesman Peter Logan says many of the claims about the financial benefits of the Grand Prix could be challenged.

"We're talking attendance, we're talking global television audience, we're talking hotel rooms, occupancy, branding," he said.

"We haven't got the money to commission senior counsel (but) we have got free advice," he said.

Grand Prix boss Andrew Westacott says the event is subject to rigorous public scrutiny.

"Every year we have external auditors, we have the Victorian auditor-general go through and then publicly table in Parliament our annual report," he said.

"It's all there. It breaks out the details of sales revenue, total revenue, expenditure.

"There's nothing hidden there, it all matches up."