China has carried out a test flight of its biggest-ever army transport aeroplane, state media said 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 has invested heavily in upgrading its military in recent years, rattling its neighbours in Asia. It insists its army spending is relatively low as a proportion of GDP and is not aimed at any other country.