Oslo (AFP) - Norway's sovereign wealth fund, the biggest in the world with shares in more than 9,000 companies, will take a closer look at the controversial issue of executive pay, the country's central bank said Monday.

"It is a theme that we will watch," Martha Skaar, a spokeswoman for the division of the Norwegian central bank responsible for managing the fund, told AFP on Monday.

The fund is worth nearly 7 trillion kroner (S$1.21 trillion) and a powerful influence on how the companies it invests in are run.

The issue of excessive executive compensation has become a hot topic for investors.

The fund will write a "position paper" to show where it stands on the issue, the spokesman said. No release date had been fixed.

In an interview with the Financial Times published Sunday, the head of the Norwegian fund announced that it planned to add its powerful voice to the debate.

"We have so far looked at this in a way that has focused on pay structures rather than pay levels. We think, due to the way the issue of executive remuneration has developed, that we will have to look at what an appropriate level of executive remuneration is as well," Yngve Slyngstad, chief executive of the fund, told the Financial Times.

Positions taken by the fund, which holds the equivalent of 1.3 per cent of world market capitalisation, are seen as important indicators to other investors.

In April, shareholders of two industrial giants, the British oil group BP and the French automaker Renault, voted against high pay proposals for the bosses of those companies, showing that the issue is a sensitive one for investors.

The Norwegian fund's investment policy is run according to strict ethical rules, with a focus on sustainable economic, environmental and social development.

Those rules bar it from investing in companies accused of serious violations of human rights, child labour or serious environmental damage, as well as manufacturers of "particularly inhumane" arms, and also tobacco firms.