The Auckland Regional Council is to formally oppose mining on Great Barrier Island, calling it unethical.
The council's regional planning and strategy committee has finished debating what to say in its submission on the Government's plan to mine protected conservation land, including Great Barrier Island.
Councillors are unanimous in their opposition, saying mining will have a negative impact on tourism and on the ecology of Auckland.
In the submission, the council says it would be ethically irresponsible for the Government to undo its promise to look after the protected land for future generations.
The council acknowledges mining is an important part of the New Zealand economy, but says it must be done in the right location - not precious conservation areas - because other industries, such as tourism, could suffer if the right balance is not struck.
Councillor Brent Morrissey says the council's move shows it is listening to Aucklanders, especially after 40,000 people turned out in protest on Queen St.
CTU weighs in against proposal
The Council of Trade Unions has also announced its opposition to the Government's proposal, saying the value of what could be mined does not outweigh the potential damage to other industries and the environment.
On Saturday, at least 40,000 people marched up Queen St in central Auckland to show their opposition.
Energy and Resources Minister Gerry Brownlee says he is not surprised by the large turnout, as it is clearly an emotional issue.
Mr Brownlee told the House on Tuesday that many of the protesters were motivated by very genuine concerns but that many of those taking part were just protesting for the sake of it.
He says the proposal to enable further exploration in some areas is moderate and is not a commitment to mining that land.
The deadline for submissions on the proposals is 26 May.
