BEIJING (AFP) - China has carried out a test flight of its biggest-ever army transport aeroplane, state media said on Sunday, as the country strengthens its military capabilities.

A successful test flight of the Y-20, a long-range heavy transport jet, took place on Saturday in the northwest of the country, the People's Daily newspaper reported on its website.

The plane was developed in China to transport military combat and support vehicles and can carry up to 66 tons, the report said, making it China's biggest home-grown military transport plane to date.

The Y-20 would be a "huge boost to the intercontinental strategic projection abilities of China's air force", the Beijing News cited an army expert as saying.

China achieved a military milestone when its fighter jet landed on its new aircraft carrier in November, extending a modernization bid that's recorded advances in submarines, cyber warfare and in outer space, Bloomberg reported.

China, the biggest spender on defence after the US, has become increasingly assertive in the region as President Barack Obama executes a strategic shift toward Asia and tensions rise with Japan and other nations over territorial disputes.

China's defense spending, estimated at 670 billion yuan (S$ 132.8 billion) in 2012, has more than doubled since 2006, tracking a rise in nominal gross domestic product to 47.2 trillion yuan from 21.6 trillion yuan.