The world's largest sovereign wealth fund, Norway's Government Pension Fund Global, is a step closer to be allowed to broaden its investments to include infrastructure as part of a strategy to increase returns.

The government will ask the $870 billion fund's Strategy Council to assess whether the fund should invest in unlisted infrastructure, the Finance Ministry said on Tuesday.

The fund will also look into raising the 5 percent cap on real estate investments.

The fund is mandated by the government to hold about 60 percent in stocks, 35 percent in debt and 5 percent in properties. The sovereign fund, which gets its capital from Norway's oil and gas wealth, is trying to move into new assets such as private equity and infrastructure.

Investments in infrastructure assets such as motorways, ports, airports and power plants, among others, will be considered by an expert team. A final decision is expected to be taken by 2016.

The previous Labor-led government in 2011 rejected the Strategy Council's recommendation to allow the move into private investments, citing "limited historical returns" on the asset class. Now the government's parliamentary support parties, the Christian Democrats and the Liberals, are supporting the move.

Few years ago, the fund increased its emerging markets investments and in 2010 was allowed to invest its capital in real estate.

On 2 December Siv Jensen, the Norwegian finance minister, said in a statement:

Developing the Fund's investment strategy through better diversification will help to ensure continued robust, long-term management of the Fund.

Mrs. Jensen added:

If general investment in unlisted infrastructure is permitted, Norges Bank will also be allowed to invest in unlisted infrastructure in the renewable energy sector and emerging markets. As with all other investments by the Fund, such investments will have to be evaluated on the basis of expected returns and risk.