Auckland Council is divided as it gets set to decide whether to allow oil exploration off the city's west coast.
Councillors will today vote whether to back the annual Government block offer for oil exploration in 2016 as part of a consultation process.
But while the council's Regional Strategy Committee narrowly backed the 2015 offer, the full council will decide on the 2016 deal, and councillors are divided on the matter.
Even Mayor Len Brown - who will have the casting vote - has expressed some concerns to media about environmental risks.
The council will hear presentations before voting on the matter, with public interest at the meeting expected to be high.
Christchurch council earlier this month said it was opposed to deep-sea oil drilling off the Canterbury coast.
The block offer system has been used by the New Zealand Petroleum & Minerals, which manages the country's government-owned oil, gas, and minerals, since 2012.
Local iwi, hapu and councils are consulted if companies express interest in exploring or drilling areas.
There are four offshore and one onshore petroleum offer for 2016, covering the entire length of the country.