Ateed has not shared the due diligence report with any city politicians.
Five councillors and Franklin Local Board chairman Andrew Baker may get to see it before the final contracts are signed this month.
The idea of possibly showing the report to a few pro-V8 councillors has annoyed other elected members, including George Wood, who said: "We are being stymied and blocked from getting the information we require."
Mr Wood likened the situation to Hamilton, where a damning Audit NZ review criticised city councillors for not asking for more information in a fiasco that cost ratepayers $40 million.
The "open" report to the committee said there was a 40 per cent risk of a cost blow-out at Pukekohe requiring a ratepayer or taxpayer bailout and a 60 per cent chance crowd numbers would not meet the target of 130,000.
Ateed officers and acting mayor Penny Hulse gave an assurance that the ratepayers' $10.6 million contribution was capped and that V8 Supercars Australia would own and underwrite the event.
Ms Hulse said the council's funding deal was $2.1 million a year over five years and "that's the end of it. It's a capped sponsorship package and not an open-chequebook proposal".
Economic Development Minister Steven Joyce said a Government contribution of up to $2.2 million towards a $6.6 million upgrade of Pukekohe Park was a "one-off" to secure the V8 Supercars in New Zealand.
The upgrade cost will be equally split between the Government, Ateed and V8 Supercars Australia.
Ateed's total contribution of $10.6 million will include $1 million a year to sponsor the weekend event, $454,000 in interest costs, $237,000 for the Counties Racing Club and $550,000 a year for marketing, transport and other costs.
The return of the V8 Supercars to Pukekohe - the event was held there between 2001 and 2007 - has the backing of Mayor Len Brown, who is currently overseas. It has strong backing, too, from Franklin councillor Des Morrison and Mr Baker, who said it would provide huge economic benefits for the local community.
Councillor Michael Goudie said the proposal was more robust than a six-point seatbelt harness in a V8 racing car. It bore no comparison to the failed Hamilton event and there was no alternative venue.
"We should be accepting the Supercar race with open arms back at its home place in Puke," he said.
Ateed's acting manager of major events, Jennah Wootten, said the organisation had considered holding the event at Hampton Downs in Waikato and backing the New Zealand-owned V8 SuperTourers, but decided the Australian-owned V8 Supercars at Pukekohe best met the criteria for a major event for Auckland and provided the greatest economic benefit.
Rail to Pukekohe aligned with Ateed's desire to provide public transport for major events.
Hampton Downs managing director Tony Roberts - who was denied speaking rights at yesterday's meeting - said Ateed had hardly spoken to him about using the Waikato race track, and talk of it being limited to 20,000 spectators was not strictly correct because it was seeking to increase this figure to 50,000.
Last night, Hamilton Mayor Julie Hardaker said her city's disastrous experience with the V8s was cited in the Government's shake-up of local government as the kind of risky commercial ventures that councils should not undertake. Now the Government was supporting Auckland's V8 event with $2.2 million, she said.
