Auckland councillors are divided about whether the city should open an area off its west coast to oil exploration.
The council will decide on Thursday whether it will allow oil exploration in the area.
The vote would form part of the council's response to the government's consultation over the 2016 block offer, which granted deep sea drilling permits to companies wanting to establish the size of gas and oil deposits in four areas.
One councillor, John Watson, said he would vote against the proposal, because the economic benefits were not worth the environmental risk.
"The actual amount of employment that comes out of this sort of activity is pretty limited, and a reasonably large number of the people involved seemed to be overseas people.
"You would have to ask yourself why you would take that sort of risk, potentially, to the environment, when the benefits seem to be so limited."
Environment, Climate Change and Natural Heritage Committee chair Wayne Walker agreed oil exploration in the area was not worth the risk.
He said the ocean off the west coast was home to critically endangered Maui dolphins, and exploration could put them under threat.
"The exploration area overlaps with the marine mammal sanctuary which was created for Maui dolphins, and whales, and other cetaceans. So this is serious," he said.
However another councillor, George Wood, said the proposal only let oil companies look for oil, and any actual extraction would come with rigourous conditions.
"New Zealand is a country that needs an economy that's viable," he said.
"We've seen what's happened off the Taranaki coast with oil and gas being extracted, and the benefits that that's brought to New Zealand and, in particular, the Taranaki economy."
He added that the proposal already included strong environmental protections for any exploration, including a buffer zone around the nearby marine reserve.
Both Mr Watson and Mr Walker said it would be a close vote - and one they could not pick ahead of time.
They also said the mayor held the casting vote if the councillors were split evenly.
But Mr Wood said when he looked at the numbers, he thought a majority of councillors would support the exploration.
The full council will vote on Thursday.