BEIJING, Aug. 28 -- Allowing China's pension fund to invest in the stock market was not intended as a bail out, but to create long-term and stable returns, said vice minister of human resources and social security on Friday.

The change will eventually have a positive effect on China's real economy and support a healthy capital market, but the core purpose was to gain long-term and stable yields for the fund, vice minister You Jun said at a press conference.

The fund's management must prioritize safety, and the timing of the fund's entry into the stock market will be decided by the market, You added.

The State Council finalized guidelines on Sunday allowing the pension fund to invest in new products, including the domestic stock market.

The guidelines allow the fund to invest in more than 20 financial products, including high-risk stocks and equities, as well as low-risk bank deposits and bonds, which diversify the investment risk, You said.

To minimize risks, the guideline restricts the maximum proportion of investments in stocks and equities to 30 percent of total net assets.

The fund will also participate in major projects and purchase shares in state-owned enterprises to gain long-term yields, he added.

Around 2 trillion yuan (330 billion U.S. dollars) of the total assets of the fund could be invested, You said, adding that the amount could be increased as the fund grows in size.

China's pension fund, which accounts for roughly 90 percent of the country's total social security fund pool, had net assets of 3.5 trillion yuan (547 billion U.S. dollars) at the end of 2014.

The pension fund was previously parked in banks or invested in treasury bonds with low yields, which had long spurred calls for change as China faces the challenge of caring for its growing elderly population.

The new policy came as China's stock markets continue to decline, beset by shrinking turnover and greater volatility. The key Shanghai index plunged more than 30 percent from its June peak, wiping out most of this year's gains.