OSLO—Two prominent Norwegian investment funds are throwing their weight behind demands that the newly elected government should push the nation's $750 billion wealth fund into making investments in renewable energy and other infrastructure projects that could provide safe alternatives to its bond and stock investments.

KLP and Storebrand AS STB.OS -3.25% Storebrand ASA Norway: Oslo kr34.26 -1.15 -3.25% March 28, 2014 5:25 pm Volume : 4.93M P/E Ratio 7.77 Market Cap kr15.41 Billion Dividend Yield N/A Rev. per Employee kr23,477,800 3635343310a11a12p1p2p3p4p5p More quote details and news » A, with combined assets under management of 780 billion Norwegian kroner ($130.1 billion), have joined several environmental organizations and the Oslo Catholic Church in calling on new Prime Minister Erna Solberg to make the changes to the fund's structure. Currently, the sovereign-wealth fund—formally called The Government Pension Fund Global—has 35.7% of its money in fixed-income investments, 63.4% in equities and less than 1% in real estate.

Having two big Norwegian asset managers back the proposal to move the fund into infrastructure and renewables could heighten pressure on Norway's incoming government to allow the fund to consider new investment strategies in order to improve its relatively modest returns, especially amid low expectations for the global bond market.

"The [sovereign fund] should be allowed to invest in infrastructure, including renewable energy and [energy] distribution in emerging markets," said Sverre Thornes, chief executive of KLP.

The proposal has been supported by environmental organizations such as Greenpeace, WWF, Zero, Friends of the Earth Norway and some Norwegian companies.

Norges Bank Investment Management, which manages the fund, sought the government's permission to invest in infrastructure in both 2006 and 2010. The center-left government in office at the time responded by saying it wanted the fund to first gain experience from other asset investments, especially real estate.

Since the establishment of NBIM in 1998, the Norwegian wealth fund has returned on average 3.17%, less than the anticipated 4% long-term average growth. The government has a self-imposed rule of spending a maximum of 4% of the fund every year.

The fund has no short-term liquidity needs and is seen as being able to carry the risk of illiquid investments in infrastructure and unlisted stocks, the investors and organizations said. Funds such as PensionDanmark and the Dutch PGGM fund already are investing in renewable energy projects.

Ms. Solberg's Conservatives and the Progress Party are aiming to form a minority government, supported in Parliament by two centrist parties. Both government parties have previously suggested that they may change the wealth fund.

"We are open for discussions," Progress Party deputy leader Ketil Solvik-Olsen said before the September elections. He suggested splitting the fund into separate pools that could invest in renewable energy and emerging markets, and also allowing independent Norwegian asset managers to manage some of the money.

The Conservative Party, however, favors stability and is unlikely to make huge changes to the way the sovereign-wealth fund is managed without a broad consensus in Parliament, including from the Labor Party, which has thus far opposed infrastructure investments.

Conservative spokesman Jan Tore Sanner recently said changes to the fund weren't a priority.

Environmental groups have urged a more diversified approach. The fund "puts money in Russian oil companies and U.K. shopping streets, but isn't allowed to invest in African solar-energy projects," Greenpeace Norway's leader Truls Gulowsen said. "That doesn't make any economical or environmental sense."