UPDATED 12.26PM A large group of protesters took over the Christchurch City Council's chambers this morning.

They included two women dressed as guardian angels, who stood in silent protest while two representatives of the group Oil Free Otautahi spoke to the Christchurch City Council.

The council today approved a submission opposing the Proposed Oil Block Offer 2017, which could see deep-sea oil drilling off the coast of Banks Peninsula.

All but one councillor voted in favour of the submission, with an eruption of cheers and applause from the protesters at today’s meeting.

However, Mayor Lianne Dalziel says they’re not the decision makers.

Retired Canterbury University senior lecturer and submitter, Dr. Paul Broady, said although they were preaching to the converted, he hopes they’ve attracted attention.

"Getting the word out and hopefully strengthening the case of the council."

It was the third deputation Siana Fitzjohn has made to a local council against proposed Oil Block Offers.

She said Christchurch has already lost a city, it’s not time to lose the environment as well.

"In a way, we are preaching to the converted, but I think there's always a chance to make that submission a lot stronger, which is what we're hoping they will do."