Saudi Arabia said it is setting up a $5.33 billion investment firm that may also be open to partners, rather than a sovereign wealth fund, and urged countries to keep their doors open to foreign investment.

"We don't have a sovereign fund but we have many investment funds," Saudi Finance Minister Ibrahim al-Assaf told delegates at a conference in the Saudi capital on Tuesday.

"What we are setting up is an investment company, not a sovereign fund."

Other Saudi officials have said previously the world's biggest oil exporter intends to set up a $6 billion sovereign wealth fund, a plan that is still in its early stages.

The finance minister told Reuters the country is "in a hurry" to begin the new agency.

"It is now being examined by the Council of Ministers. The approval should come about within the usual timeframe," he said.

Sovereign wealth funds, many based in oil-producing countries as well as key Asian exporters such as China, control between $2 and $3 trillion in assets.

Investments by the funds have raised concern about their potential political motives among Western countries, some of which are considering restrictions on their activities.

The Saudi finance minister noted on Tuesday that the new agency would be smaller than other state-owned funds in the Gulf. "We would like to invest in profitable, low-risk assets," he said, without being more specific.

"I reiterate the importance of avoiding restrictions on flows of capital ... whether these are coming from emerging countries or the opposite." 

Last week, the International Monetary Fund and 25 sovereign wealth funds established an international working group to draft best practice guidelines for state-owned funds.

The guidelines in governance and transparency are aimed at helping ease worries about the funds' growing size and influence, since many reveal little about their investments. -Reuters