Delegates to the Petroleum conference make it into the venue under mass police escort.

The presence of protesters attempting to disrupt a controversial oil and gas conference hasn't put Wellington authorities off hiring TSB Arena out to the group in the future.

About 200 demonstrators tried to prevent delegates entering the central Wellington venue for the Petroleum Exploration and Production Association of New Zealand (Pepanz) conference before dawn on Tuesday.

While one man was injured and four protesters were arrested, a spokesman for Pepanz said the conference went ahead as planned.

ROSS GIBLIN/STUFF Protesters link arms outside the conference at TSB Arena in Wellington.

Delegates had been escorted into TSB Arena, along with Energy Minister Megan Woods who addressed the event.

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Protesters made their presence felt by surrounding the venue, tying themselves to entrances with zip ties, banging on the side of the building and some jostling with the large police contingent.

ROSS GIBLIN/STUFF Police scuffle with protesters to let delegates in to the Petroleum Conference at TSB Arena.

Wellington Regional Economic Development Agency (Wreda) handles the indoor arena's operations.

Its venues, marketing and destination development general manager, David Perks, said it would have no issue hosting a Pepanz conference in the future.

"We respect people's right to protest, but ask all participants to consider the safety of our staff and event attendees.

ROSS GIBLIN/STUFF An injured man is attended to at the protest outside the conference.

"Wreda opens up its venues for hire to all businesses that operate legally in New Zealand and we welcome people attending this conference as we would any other," Perks said.

Inspector Brett Amas said two men, aged 22 and 19, have been charged with assaulting police while a 20-year-old woman was arrested for obstructing a public place and was given a pre-charge warning.

A 38-year-old man was charged with breach of the peace.

ROSS GIBLIN/STUFF Climate change protesters blocking all entrances to Pepanz oil and gas conference in Wellington.

Amas said police responded to a call for assistance regarding the injured man, who was in his 50s, but he declined any police help.

"The role of police at these type of events is to ensure safety and uphold the law while recognising the lawful right to protest."

Protest co-organiser India Logan-Riley said the injured man had been concussed and was treated by ambulance staff.

KATARINA WILLIAMS/STUFF Former Green Party co-leader Jeanette Fitzsimons joins protesters outside the Pepanz oil and gas conference.

Rally for Climate Justice spokesman Teanau Tuiono said police were "a bit rough" and "over the top".

The protest had been organised to stand up to oil companies that were "wrecking" the climate.

"People are literally dying because of the climate change caused by fossil fuel industries and we're saying it needs to stop now," Tuiono said

ROSS GIBLIN/STUFF Police cut chains put on one of the entrances to TSB Arena.

"We intend to disrupt this conference. We intend to shut it down. We did the same thing last year in Taranaki. They didn't get the message. This year, we're louder and prouder."

Coal Action Network Aotearoa protester and former Green Party co-leader Jeanette Fitzsimons joined the protest.

"A big victory would be that the oil industry stopped having these conferences because this conference is all about trying to get more oil out of the ground in Aotearoa - and we don't want that," she said.

"We have been sitting here non-violently resisting while the police pushed us in the backs with their knees, and in the end they realised it was a bunch of over-70s holding the line. [Police] backed off and they haven't got anybody through this entrance, which has been blocked."

The Pepanz conference is set for three days and has been marketed as the industry's "premier" oil and gas event.

The conference includes senior government officials, regulators, industry leaders, international experts and service providers.