BEIJING -- China's revamped pension investment plan is expected to be unveiled by the end of the year.

The State Council, China's cabinet, is deliberating on the plan and taking into consideration public opinions on investing the fund.

China hopes to achieve a diversified investment plan for its pension fund, in response to criticism over its rigid management and low returns over the past two decades.

Previously, the pension fund was only deposited in banks or invested in treasury bonds. An estimate from Chinese Academy of Social Sciences said the fund depreciated by nearly 100 billion yuan ($15.7 billion) in the past 20 years.

The revamped plan will allow the money to be invested in government and corporate bonds, major construction projects, leading State-owned enterprises and the stock market.

The fund, which accounts for roughly 90 percent of the country's total social security fund pool, had net assets of 3.5 trillion yuan ($548 billion) by the end of 2014.

Around 2 trillion yuan will be allowed to be put in the market, according to the Ministry of Human Resources and Social Security.

Though the exact amount of money that can be channeled into the stock market is still unknown, a guideline issued earlier has stipulated a 30-percent cap, given the huge risks existing in the volatile equity market.