Ex-Beatle Paul McCartney, actress Penelope Cruz and director Robert Redford have joined a campaign for a "global sanctuary" around the North Pole, Greenpeace announced Thursday.

They are among the first 100 names on a planned million-signature scroll that the green group wants to place on the seabed beneath Earth's northernmost point.

The spot will be marked with a "Flag for the Future" designed by children in a global competition organized by the movie star-Girl Guide movement.

Its goal is to counter nationalist claims on the North Pole and preserve the heart of the Arctic Ocean from a carve-up for resources.

Greenpeace International executive director Kumi Naidoo said the aim would be to push for a UN resolution demanding a global sanctuary around and under the Pole.

"The Arctic is coming under assault and needs people from around the world to stand up and demand action to protect it," he said at the launch of the campaign at the UN development sustainable summit, or Rio+20.

"A ban on offshore oil drilling and unsustainable fishing would be a huge victory against the forces ranged against this precious region and the four million people who live there.

"And a sanctuary in the uninhabited area around the pole would in a stroke stop the polluters colonizing the top of the world without infringing on the rights of indigenous communities."

British tycoon Richard Branson and "Warrior Princess" actress Lucy Lawless, who took part in an occupation of a Shell Arctic oil rig, added a celebrity sprinkle to the launch.

Branson described his trip to the Arctic on a dog sleigh, calling the region "one of the most spectacularly beautiful parts of the world" and gravely at risk.

The first 100 signatories include "Slumdog Millionaire" star Dev Patel, actors Hugh Grant and Emily Blunt as well as musicians Bryan Adams, Peter Gabriel, Thom Yorke, the Red Hot Chili Peppers, boy band One Direction and China's Xiao Wei.

The shrinkage of Arctic ice through global warming has led to jostling over sea routes and access to the sea bed, which is believed to be rich in hydrocarbons and minerals.

Countries that border the Arctic are Russia, Canada and the United States, as well as Norway and Denmark, through Greenland.

In 2007, Russian explorer Artur Chilingarov planted a Russian flag on the seabed under the North Pole, saying he claimed it for Russia.

The claim was orchestrated by the Kremlin and has no legal validity, according to critics.