Auckland mayor Wayne Brown is pouring cold water on talk of his council's rubbish going north to a proposed $730 million Kaipara waste-to-energy plant.

This comes as a Kaipara waste-to-energy plant opponent challenges Kaipara mayor Craig Jepson's indications that Auckland rubbish will fuel the controversial Northland-based industrial facility, along with a much-smaller amount from the North.

Stop the Kaipara Waste Incinerator member and Kaipara ratepayer Jane Reed, who has waste management experience, said Auckland rubbish was not in line to head north.

Under the proposal, Auckland rubbish would make up about 95 percent of the waste-to-energy plant's fuel and be essential to the plant's existence.

The balance would come from Northland.

An Auckland Council Official Information Act (OIA) request response to Reed formally confirmed Brown had discussed the proposed waste-to-energy plant with Jepson.

But it said Auckland Council had not entered into any negotiations with KDC or the plant's proponents, neither was there any timeline for sending Auckland's rubbish to Kaipara.

Kaipara mayor Craig Jepson. Photo: Northern Advocate / Michael Cunningham

Local Democracy Reporting Northland asked Brown for his position on sending his city's rubbish to the Kaipara plant.

The mayor's spokesperson said Brown visited Jepson on other matters, and the plant and its technology were discussed as a matter of interest, but no plans or decisions had come of the meeting.

It was not an Auckland Council project and Brown had not committed any of Auckland's rubbish going to the Kaipara plant, the spokesperson said.

Jepson said securing Auckland's waste was essential for building the Kaipara plant.

He said sourcing the waste fuel for the Kaipara waste-to-energy would be part of the necessary due diligence for building the plant.

An Auckland Council spokesperson said that council was aware of KDC's desire for a waste-to-energy plant in Northland, however, it was not leading the project, nor did it have any role in its development.

"In principle, Auckland is interested in new waste minimisation technology that can minimise waste sent to landfill," the spokesperson said.

The spokesperson said most of Auckland's waste sent to landfill was commercial and collected and processed by private waste companies.

KDC is working with majority-overseas owned South Island Resource Recovery Limited (SIRRL) on its potential waste-to-energy plant for Kaipara.

The same company is pushing to build a waste-to-energy plant near Waimate, south Canterbury.

A decision on this is with the Environment Court.

SIRRL had presented to Auckland Council last year, the spokesperson said.

"The South Island Resource Recovery Limited (SIRRL) presented their Waimate concept to Auckland late last year. This was a learning and information exercise, but that has been the extent of our participation to date," they said.

Jepson said he was not concerned by Auckland Council's current position.

"I think it's early days yet, they're not going to have a proper response until there is an application (to build the waste-to-energy plant) from a private entity," Jepson said.

Auckland Council's waste policy ran until 2028 and it would take three years to build the waste-to-energy plant in Kaipara, he said.

Jepson said he had not had conversations with the private waste companies which manage Northland and Auckland's rubbish disposal.

Reed's OIA response said Auckland Council's new draft waste minimisation plan included that waste to energy production took many forms "and that some proposals such as capturing landfill gas and energy from anaerobic digestion of food scraps may be appropriate".

However, other more complex proposals such as the proposed Kaipara waste-to-energy plant would have impacts which would need to be assessed against Auckland's waste minimisation goals.

These included Auckland being zero waste by 2040.

Far North and Whangārei district council mayors were also recently lukewarm on their rubbish going to the Kaipara waste-to-energy plant.

LDR is local body journalism co-funded by RNZ and NZ On Air.