The world’s largest seaplane rolled off a production line in China at the weekend, beefing up the country’s strategic reach to islands it claims in the South China Sea.

While not ruling out military uses, state news agency Xinhua said the amphibious aircraft, which is the size of Boeing 737, would be deployed to “fight forest fires and perform marine rescue missions”.

State-owned Aviation Industry Corporation of China, which designed and produced the seaplane, had 17 orders so far, Xinhua added, noting that the aircraft would be “very useful in developing and exploiting marine resources”.

The AG600, which boasts four turboprop engines and a hulking body with a keel down the centre of the plane’s belly, could also be used for “environmental monitoring, resource detection and transportation,” Xinhua said .

The article said the AG600 has a range of 4,500km — a distance that comfortably covers much of the western Pacific Ocean from China’s coast, and as far as the northern shores of Australia.

According to Chinese media reports, the aircraft is capable of carrying 12 tonnes of water for dousing forest fires, and could rescue up to 50 shipwreck victims at a time.

However, the AG600 also adds to China’s military additional capabilities in the South China Sea, where Beijing is locked in an escalating war of words with neighbouring countries such as Vietnam and the Philippines — as well as the US — over its efforts to build islands in disputed waters.

Seaplanes last saw large-scale military use by the US against the Japanese during the second world war’s “island hopping” Pacific campaigns. However, they are little used by modern military forces.

The aircraft gives Beijing the capacity to connect to island bases in remote locations without available airfields.

The seaplane follows hot on the heels of the launch of the Y-20 Kunpeng, nicknamed the “chubby girl”, which is the largest military transport aircraft currently in production and is designed to help the People’s Liberation Army fulfil a more global mission, capable of sending troops and tanks around the world at a moment’s notice.

Last year China published a white paper presenting a broad rethink of its defence policy, emphasising the evolution of the country’s security needs away from simple territorial defence towards an offensive capacity overseas.