"Xena: Warrior Princess" actress Lucy Lawless was arrested in New Zealand Monday after occupying an oil-drilling ship for three days to protest plans to search for oil off Alaska, Greenpeace said.

Police climbed a 53-metre (175-foot) drilling derrick on the ship Noble Discoverer in the North Island port of Taranaki and arrested Lawless, along with five other Greenpeace activists, the environmental group said.

The actress boarded the vessel early Friday in a bid to prevent it sailing to the Arctic, where it has been contracted by Anglo-Dutch energy giant Shell to conduct exploratory drilling.

"This chapter has ended, but the story of the battle to save the Arctic has just begun," said Lawless in a statement.

The New Zealander, who starred as the title character in the fantasy television series "Xena: Warrior Princess" from 1995-2001, is a long-time environmental activist who was named as a Greenpeace ambassador in 2009.

Greenpeace said she and her fellow protesters were expected to be formally charged later Friday. Police were not immediately available for comment.

Lawless told AFP on Friday that she was not concerned at the prospect of being arrested over the demonstration.

"That's the least of my concerns," she said. "I'm a true believer. We need to start switching over to renewable energy now, we don't have to go to the ends of the earth to suck out every last drop of oil."

The US Interior Department granted Shell conditional provisional approval to begin drilling exploration wells in the Arctic Ocean last August, in a move slammed by conservationists as "inexcusable".

US officials had pledged to closely monitor Shell's plans for four shallow water exploration wells in Alaska's Beaufort Sea to ensure operations are conducted in a "safe and environmentally responsible manner".

But green groups say it puts wildlife and native communities in the remote region at risk, citing the vastly complicated task of drilling in the harsh Arctic environment and effectively cleaning up any spills in such conditions.

They also point to the environmental catastrophe in the Gulf of Mexico in 2010 after Shell's Deepwater Horizon rig exploded as an example of the risks inherent in drilling for oil.

Photo by Gage Skidmore [CC-BY-SA-3.0 (www.creativecommons.org/licenses/by-sa/3.0)], via Wikimedia Commons