Secret plans to build a new stadium on prime land at Auckland's waterfront with private money have been revealed.

The plan, put forward by a group of business people, was to build a stadium partly sunken into reclaimed land at Bledisloe Wharf.

It had been provided to a range of public agencies and officials, on condition they signed non-disclosure agreements, Newsroom reported today.

Auckland Mayor Phil Goff confirmed in a statement to the Herald that he knew of the plan, but did not speak to allegations of secrecy.

"I have been approached by a private sector consortium of local businesses who are interested in building a downtown stadium," Goff said.

"Council is not in the position to finance a stadium through ratepayer funding and it is not on our current list of priorities.

"We are however open to considering a national stadium being funded from the private sector.

"I would welcome public debate around the design and location of any stadium which would provide council with valuable feedback on possible options for the future."

Goff had raised the prospect of a new stadium shortly after coming to office in 2016 and had received a pre-feasibility study from PwC, costing $932,000, recommending a run-off between five possible downtown sites and upgrading Eden Park.

He received criticism this year from councillors over his refusal to give them full and open access to the report.

Goff said earlier this year there was no money in the council's 2018-2028 budget for a stadium.