The Norwegian wealth fund, set up in 1996 to save petroleum revenues for future generations, operates under ethical guidelines set by parliament and excludes investments in companies that it says does not respect the guidelines.

The fund, which holds stakes in more than 9,200 companies globally, on Thursday said the exclusion of Power Construction Corp of China was because of "unacceptable risk of the company contributing to or being responsible for serious environmental damage", citing its hydropower development in Batang-Toru in Indonesia.

Its stake in Power Construction Corp of China was 0.03% at the end of last year, valued at $4.1 million.

Power Construction Corp of China Ltd did not immediately respond to a request for comment.

The fund, which owns about 1.5% of all globally listed shares, also said it had placed London-listed oilfield services company Petrofac under observation for three years, citing "unacceptable risk of gross corruption or other serious financial crimes".

Petrofac reached a deal in 2021 with Britain's Serious Fraud Office (SFO) and was fined after pleading guilty to paying bribes related to contracts in Iraq, Saudi Arabia and the United Arab Emirates between 2011 and 2017.

"The SFO's investigation into Petrofac concluded in October 2021 and all penalties imposed by the court have been paid by the company. Today Petrofac has a comprehensive and robust compliance and governance regime," a Petrofac spokesperson said.

The fund's stake in Petrofac stood at 1.19% at the end of 2022 and was worth $5.25 million at the time, the fund's website says.

(Reporting by Victoria Klesty; Additional reporting by Shadia Nasralla in London and Brenda Goh in Shanghai; Editing by Diane Craft and David Goodman)