Wellington building cordoned off due to anti-mining protest

Five people have been arrested after a Greenpeace protest outside the Wellington office of mining lobby group Straterra, which caused police to cordon off an office building.

The activists were protesting Straterra's plans to fast-track a seabed mining project for one of its clients, Trans-Tasman Resources, in the South Taranaki Bight.

Two protesters climbed on to a ledge outside the building on The Terrace on Tuesday morning, and at least one other managed to enter the office building.

Two police cars, a van and two fire trucks attended, and the area around the building was cordoned off for health and safety.

Fire and Emergency senior station officer Pati Salanoa said they had removed three people from inside a locked building, and they were now in police custody.

At its peak, about 30 people were watching from the street, with some unable to enter their workplaces.

In a statement, Greenpeace said it was "a demonstration of the resistance promised" in a recent open letter to companies considering using the fast-track process, which aims to speed up infrastructure consenting.

More than 7500 people had co-signed the letter, Greenpeace said.

The group called Straterra a "malignant force in New Zealand politics, operating in the shadows and backrooms to exert a pernicious influence over Government policies".

Campaigner Juressa Lee told RNZ the disruption was justified.

"This is a peaceful protest, and peaceful protest is an important and legitimate part of civil society. I'm very concerned. We're in the midst of a climate crisis."

She said Greenpeace had "tried lots of different avenues", including written and oral submissions, a petition and protest march.

"We are putting companies that wish to use the Fast-track Approvals Bill to get their polluting projects over the line, on notice... This is the kind of action that we're prepared to take in order to protect our environment."

Trans-Tasman Resources declined to comment. RNZ has also approached Straterra.