The carrier, known only as "Type 001A", set out for the trials on Sunday morning, according to official news agency Xinhua, while state broadcaster CCTV said the ship left a port in northeastern China around 6.45 am (2245 GMT Saturday).

Expected to be commissioned by 2020, the ship will give China a second aircraft carrier to beef up its navy as it asserts its claims in the disputed South China Sea and seeks to deter any independence movements in Taiwan.

China's sole operational aircraft carrier, the Liaoning, is a repurposed Soviet ship bought from Ukraine, which went into service in 2012.

The possession of a native aircraft carrier places China among the few military powers with such vessels, including the United States, Russia and Britain.

But it would still be no match in size or range to the nuclear-powered vessels of the United States Navy, which has 11 carriers.

Beijing has embarked on an extensive project to build a "blue water" navy and modernise its two million-strong military, the world's largest.

The Type 001A carrier will displace 55,000 tonnes and use conventional rather than nuclear propulsion, according to the defence ministry.

Chinese experts estimates the carrier could be ready for action in about two years after further tests.