Sword-and-sandal screen star Lucy Lawless, who along with seven other Greenpeace protesters today pleaded guilty to boarding and occupying an oil drilling ship, says she did what she had to do.

Lawless - under her real name Lucy Tapert - Jan Raoni Hammer, Mike Buchanan, Shayne Comino, Vivienne Hadlow, Shai Naides, Zach Penman and Ilai Amir, appeared in the Auckland District Court this morning.

The group was arrested after they boarded and spent four days aboard the Shell oil exploration ship the Noble Discoverer at Port Taranaki in February.

They scaled the 53m-high derrick of the ship, camped out and unfurled banners reading "Stop Shell" and "Save the Arctic".

The oil ship was scheduled to leave the port to drill three exploratory oil wells in the Chukchi Sea off the coast of Alaska, but the journey was delayed due to the protesters' actions.

They were charged with burglary but today pleaded guilty once their charges were reduced to illegally boarding a ship.

Outside court, Lawless said she had "no plans to reprise her role on an oil rig" but her association with Greenpeace would continue.

"I had to do what I had to do," she said.

While it may have been risky for her career "It's not as risky as doing nothing," she said.

Her message to Shell and governments undertaking deep-sea oil drilling was: "Under no circumstances is this a good idea".

"They are robbing our children of their birthright to a clean and healthy planet, and they know it."

Greenpeace spokeswoman Viv Hadlow said 475,000 people had signed on to the Greenpeace campaign against Shell's "insane plans" to drill in the Arctic.

The involvement of Lawless, the star of the cult show Xena: Warrior Princess, drew international attention to their cause.

Steve Abel, a Greenpeace climate campaigner, who was at the Taranaki port, said it was one of the longest lasting occupations in recent history in New Zealand.

"If there was an oil spill in the Arctic it would be impossible to clean up," Abel said. "This is what this is about."

Judge David Holderness remanded the group on bail to sentencing on September 14 in the New Plymouth District Court.

- © Fairfax NZ News