BEIJING - China's top economic planner has approved the construction of six railways stretching more than 1,000 km and likely to cost about 250 billion yuan ($40.8 billion), in a move it hopes will help stabilize economic growth.

The projects include four high-speed railway lines in eastern provinces of Shandong and Jiangsu, and in northeastern province of Liaoning, and two urban rail transits in the southwestern cities of Chengdu and Nanning, the National Development and Reform Commission (NDRC) said on Monday.

It did not specify how the central and local governments will fund the projects. Another NDRC document issued on Monday said the government will promote public-private partnerships to attract private capital into infrastructure construction and public enterprises. The reform in railway investment and fund-rasing will be deepened, it said.

As Chinese authorities adapt to the country's plateauing economy, the NDRC said earlier this year that it would "increase management of investment" in 2015 and give investment a "key role in stabilizing economic growth".

Targeted macro-regulation will be used to better direct investment, improve projects' profitability, strengthen vulnerable areas in economic and social development.

In 2014, the NDRC approved projects worth 34 billion yuan for transportation infrastructure including railways, roads, airports and waterways.

China's economic growth slowed to 7 percent in the first quarter this year, down from 7.3 percent in the previous quarter, fuelling speculation that further policy easing measures are on the horizon.