A Boeing 737 passenger jet with almost 50 people on board has crash-landed in a lagoon in the Pacific state of Micronesia.

The plane, operated by Papua New Guinea state airline Air Niugini, hit the water short of the runway while attempting to land at Chuuk Island.

Dramatic footage emerged showing the 47 passengers and crew being rescued in boats from the half-submerged plane. One passenger posted a video to social media saying the aircraft was filled waist-deep with water before the first rescuers arrived.

The airline said in a brief statement that all those on board were able to evacuate safely.

An airport manager said the incident happened at around 9.30am local time.

“It was supposed to land but instead of landing it was 150 yards short and she went down,” Jimmy Emilio, general manager of Chuuk Airport, told the Reuters news agency.

“We don’t really know what happened ... people were rescued by boats – 36 passengers and 11 crew were all rescued, only the plane is sinking right now,” he said.

The plane crash-landed in a lagoon (US Navy/AP)

A local hospital spokesperson said the passengers and crew were all taken to hospital, where eight remained, four in a serious condition with bone fractures and other injuries.

“I thought we landed hard until I looked over and saw a hole in the side of the plane and water was coming in,” passenger Bill Jaynes said in a video posted by the Pacific Daily News website.

“I thought, well, this is not like the way it’s supposed to happen,” he said. He said the water had risen up to waist height in the cabin before rescuers arrived.

Air Niugini has been in operation since 1973, and its fleet includes Boeing 767 and 737 jets for international routes.

Boeing said in a brief statement that it was “glad to hear” initial reports that all passengers and crew evacuated the sinking plane safely. The company said it would “provide technical assistance under the direction of investigating government authorities”.