An Air Niugini flight, bound for Port Moresby, has overshot its runway and landed in water.

新几内亚航空公司一架飞往莫尔斯比港的航班，冲出跑道落入水中。

Reports of numbers on board vary, although according to local media all passengers and crew were promptly rescued and are safe, although the aircraft itself, a Boeing 737-800, is now fully submerged.

Small private boats were the first on hand to assist the downed aircraft, with authorities arriving soon after.

Images and video posted on social media show local fishermen surrounding the partially submerged aircraft, close to which life rafts had also been deployed.

Air Niugini is the national carrier of Papua New Guinea and had recently expanded its international services.

It is not yet known what caused the crash.