The fund, which invests Norway's vast surplus of oil money and is among the world's largest investors, will also take direct charge of some future real estate investments.

The changes, which will continue a shift in policy since 2011, will be made before 2016.

"New frontier markets will be added to our equity investments and the scope of our fixed-income investments will be widened to include additional currencies," the fund said in a statement on Tuesday.

The fund, worth about $173,000 for every man, woman and child in Norway, invests in more than 8,000 firms and across 82 countries. It owns 1.3 percent of the world's listed companies, including 2.5 percent of European ones.

Set up as a sovereign wealth fund in 1998, the fund's net annual return has lagged its 4 percent target, prompting a shift in its investments three years ago from Europe to emerging markets. It invests in stocks, bonds and real estate only.

The fund has said it plans to take a more active role in some of the firms it invests in, increasing its stake in those companies to over 5 percent. On Tuesday, it said it aimed to increase their number to 100 by 2016, and that two-thirds of them would be in Europe.

As of Dec. 31, the fund held stakes of more than 5 percent in at least 10 companies, including Finnish forestry firm Stora Enso (>> Stora Enso OYJ) and Hong Kong's China Water Affairs Group Ltd (>> China Water Affairs Group Ltd.).

REAL ESTATE

Investments in real estate currently represent 1 percent of the fund's portfolio, but will rise to 5 percent over time.

On Tuesday the fund said it expected to invest 1 percent of its portfolio in property in each of the next three years and that it would become a more involved real estate investor.

"Our real estate investments to date have primarily been implemented through joint venture agreements. We will prepare the organisation for management of fully owned properties and a more active role in the development of our properties.

"Larger ownership stakes in listed real estate companies and public-to-private transactions will be considered," it said.

The fund said property investments would be focussed on a limited number of major cities.

"Our U.S. investments will be concentrated in New York, Washington D.C., Boston and San Francisco. In Europe, investments outside London and Paris will be selectively extended," it said.

"We will also consider investment opportunities in global cities outside Europe and the United States.""

(Reporting by Gwladys Fouche, editing by Terje Solsvik and Catherine Evans)

Stocks treated in this article : Stora Enso OYJ, China Water Affairs Group Ltd.