Auckland City Council (ACC) will not respond to requests for funding to underwrite some of the cost of the Eden Park revamp until it has seen a business case, Mayor John Banks says.

The stadium is being redeveloped for the 2011 rugby World Cup, but funding shortfalls mean the Eden Park Trust Board is seeking ways to financially back the work while it seeks sponsorship deals.

ACC is spending $28 million to improve infrastructure surrounding the park and support the event, but has not contributed cash to the park redevelopment, maintaining it is a national project which should get national funding.

The Eden Park Redevelopment Board (EPRB), set up under agreement between the Government and the trust board, said there were always going to be funding shortfalls which needed filling, and that had not been helped by the grim financial climate making it hard to attract sponsorship.

Auckland Regional Council (ARC) has earmarked $10m for the redevelopment and EPRB chairman John Waller this morning said he hoped other local councils would chip in.

Rugby World Cup Minister Murray McCully said the extra money needed to come from Auckland.

"In the same way that other centres around New Zealand have risen to the challenge, Auckland is going to have to rise to this challenge," he told Radio New Zealand.

"Taxpayers have more than met their fair share of it, and I've made it very clear to the trust board that the remaining funds need to come from the source that was always intended - and that was from within the region."

Mr Banks has been adamant that ratepayers shouldn't have to fork out for the stadium and said he wasn't ready to respond to requests for funding underwrites understood to be up to $40m.

"There is a long way to go before we start signing up in the absence of the business plan," he said. "We just need to hold this with light hands at the moment."

He said he understood such a plan was prepared, but was waiting to hear from Mr McCully and the trust board.

Mr Banks said while the ARC had promised $10m, which was yet to be seen, other councils in the Auckland region had not contributed a cent to the project.

The council understood the need to ensure the project was completed on time and was confident that would happen and the event would be a success.

Mr Waller said the redevelopment was on track to be completed by its October deadline.