Greenpeace activists on Thursday diverted oil executives from a meeting on prospecting possibilities off Greenland and instead gave them a 20-minute environmental lecture, the group said.

Eighteen representatives of oil giants like Shell, BP, Chevron and Statoil, had been invited to the Copenhagen meeting by the Greenlandic Bureau of Minerals and Petroleum to discuss prospecting for the black gold in the waters off the autonomous Danish territory.

Around 20 suit-and-tie-clad activists from Greenpeace, which is ardently opposed to any drilling in the fragile Arctic ecosystem, met some of the oil executives in the lobby and, pretending to be their hosts, ushered them to a different floor.

"We had found out that the Greenlandic Bureau of Minerals and Petroleum had invited these representatives to a meeting in Copenhagen today," local Greenpeace spokeswoman Karen Albertsen said.

"The meeting was supposed to take place on the fifth floor of the building. We therefore rented the fourth floor under the name of a fake computer company," she added.

Once the participants were seated in the wrong meeting room, the disguised activists showed them a 20-minute presentation about the environmental risks posed by exploiting oil off Greenland, Greenpeace Arctic specialist Jon Burgwald said.

None of the represented companies could be immediately reached for comment, but the Greenlandic Bureau of Minerals and Petroleum confirmed to AFP that "some of the people invited (to the meeting) were detoured to another floor."

Greenland, an autonomous Danish territory, is looking to oil prospecting as a way to establish its economic independence.

Greenpeace has launched a number of actions to halt prospecting off Greenland, most recently in June when two activists, including the head of the environmental group, scaled a Cairn Energy rig to halt its drilling there.

Three months later, the Scottish group abandoned its explorations off the Arctic island, saying it had found only minor amounts of oil and gas.

The Arctic holds 90 billion barrels of oil and 30 percent of the world's undiscovered natural gas, according to US geological experts.