Members of the Royal New Zealand Air Force are helping in a search and rescue mission in Fiji after an alleged "horrific" incident on a fishing vessel saw members of the crew jumping overboard.

At least one survivor has been found by a NZ Air Force P-3 Orion, according to the local co-ordination centre and Republic of Fiji Navy.

Up to six crew members went overboard on Wednesday after an incident that has been described as "horrific" allegedly took place on a fishing vessel along the Yasawa and Mamanuca waters.

FBC News site reports that the horrific nature of the incident had prompted those crew members to jump into the water.

At least two other crewmen remain on board the vessel.