China's top economic planner introduced a new list of public-private partnership (PPP) projects involving 2.14 trillion yuan (320.7 billion U.S. dollars) of total investment on Wednesday as part of its efforts to promote investment amid an economic downturn.

The 1,233 projects cover energy, transportation, water conservancy, agriculture, forestry and public works, the National Development and Reform Commission (NDRC) said.

They were selected from a total of 2,053 projects submitted by local governments, according to the NDRC.

The move followed the introduction of two lists of PPP projects since May 2015. Of those projects, contracts for 619 projects with a total investment of 1 trillion yuan had been signed as of the end of July.

PPPs are collaborative projects between governments and private companies.

Chinese authorities have explored funding infrastructure and public works through the PPP model since late 2013 amid growing concerns over rising local government debt incurred through local financing vehicles.

In September 2015, the Ministry of Finance started a fund with180 billion yuan to support the financing of PPP projects.

The NDRC has also accelerated the approval of new fixed-asset investment for major infrastructure projects to sustain economic growth.

The efforts have already taken effect to some extent, with fixed-asset investment growing 8.2 percent year on year in August, up by 4.3 percentage points from the previous month, official data showed.