"We have been advised by our lawyers that the company's conduct gives rise to legal claims under German law," the company said in a statement.

Volkswagen admitted last year that it had installed secret software to cheat US emissions tests.

Norges Bank Investment Management is one of the company's biggest investors.

It is worth $850bn (£592bn; €751bn) and has stakes in more than 9,000 companies.

According to the Financial Times, which first reported the story, the lawsuit is expected in the coming weeks. It will be filed in Germany, joining class-action cases which are being prepared there.

"Norges Bank Investment Management intends to join a legal action against Volkswagen arising out of [the fact that] the company provided incorrect emissions data," the statement, seen by Reuters news agency, said.

"As an investor, it is our responsibility to safeguard the fund's holding in Volkswagen."

Volkswagen has put aside some €16.2bn to pay for the emissions scandal.

Last month the German carmaker reached a deal with US authorities in which it agreed to offer "substantial compensation" and car buy-back deals. Final details are expected in June.

The Norwegian fund recently announced action to clamp down on excessive executive pay at the companies it invests in, as well as encouraging oil firms to report more on the risks of climate change.

(BBC)