Details of rules on private investment in State-monopolized sectors will be published before the end of June, according to the National Development and Reform Commission, China's top planning agency.

"The focus will be to widen market access to stimulate the vitality of private capital," Li Pumin, spokesman for the commission, was quoted by China National Radio as saying on Tuesday.

As pledged by Premier Wen Jiabao in the government work report delivered in March, details of the "New 36 Clause", a rule that allows private companies to invest in sectors previously monopolized by State-owned enterprises, should be formulated within the first half of this year.

The policy was first published in May 2010 but questions have been raised about the effectiveness of its implementation because private investors still encounter "glass doors" in many sectors.

A series of policies to encourage private investment in their sectors has been released by railway, healthcare, securities and banking regulators in the last month.

But more are still expected in sectors including energy and telecommunications. There are only about 20 days left for policies to be unveiled before the deadline arrives.

In response to concerns over another round of massive fiscal stimulus that could further unbalance the economy, Li said investment would still be an "indispensable" measure in the nation’s industrialization and urbanization process.

However, the key is to optimize the structure of the investment while strengthening any weakness in social and economic development, Li said.

weitian@chinadaily.com.cn