Under the unanimous deal, the fund will sell all shares in companies that get more than 30 per cent of their turnover or activity from coal. The right-wing government and the fund itself will have to work out exact definitions.

Environmentalists hailed the vote, mainly targeting mining companies and power generators, which was expected after a bipartisan decision by a key parliamentary committee late last month.

"Norway's decision to take a stand against coal is an example for other governments – and for investors – about shifting from polluting energy sources towards clean, renewable power," Greenpeace International head Kumi Naidoo said.

The central bank, which manages the fund, has indicated it may have to sell shares worth up to 40 billion crowns ($6.5 billion) in up to 75 companies.

Greenpeace and other environmental groups estimated a higher total of 122 companies, with shares valued at 67.2 billion crowns.

Burning coal releases large amounts of greenhouse gas. Norway has had little debate about wider divestment from fossil fuels, a sensitive subject since the fund itself is built from Norway's offshore oil and gas revenues.

Environmentalists predict sales in European and US power companies including Duke Energy, RWE AG, American Electric Power and Dominion Resources.