BEIJING - China's national space agency said on Tuesday it will soon announce rules to regulate commercial rocket manufacturing, test flights and launches, state media reported, as the number of private startups in the nascent sector surged in the past year.

A space law has been included in the legislative plan of parliament, and could be introduced in the next three to five years, China Space News reported, citing a presentation at an industry conference in Hunan province.

The number of private firms engaged in the commercialisation of China's space industry have increased to almost 100 from 30 last year, including manufacturers of rockets and satellites, according to China Space News.

Commercial space enterprises must strictly follow state regulations on safety and confidentiality to protect national security, Wu Yanhua, deputy director of the China National Space Administration, was cited as saying at the conference.

Space startups are racing to develop rockets capable of delivering low-cost micro-satellites with commercial applications. None of them has succeeded yet, but that has not stopped Chinese venture capital from pouring fresh financing into the sector in recent months.

Beijing has encouraged private investors to participate in its push in a bid to commercialise some aspects of the space industry, setting up funds and opening up government launch sites for their use.

One of China's near-term tasks is to develop major satellite systems of remote sensing, communications and navigation, according to a government white paper in December 2016.

China will mark its 4th annual Space Day on Wednesday as it celebrates its achievements in aerospace and telegraphs its ambitions to explore the moon and other celestial bodies.

(Reporting by Ryan Woo; Editing by Kim Coghill) ((Ryan.Woo@thomsonreuters.com; Reuters Messaging: ryan.woo.reuters.com@reuters.net))