Four die as light plane crashes into ocean off Redcliffe, near Brisbane

Water police and the coast guard are trying to access the plane. (ABC News)

Four people have been killed after a small plane crashed into the sea off Redcliffe, north-east of Brisbane, Queensland police say. 

The plane crashed off the end of a runway at Redcliffe and into the sea shortly after 9:00am AEST on Sunday.

Police Inspector Craig White said police divers recovered the bodies of two men and two children from the wreckage about noon.

Police confirmed on Sunday night that the pilot was a 67-year-old Wamuran man.

His three passengers were a 41-year-old Brisbane man, his 10-year-old daughter and nine-year-old son.

Inspector White said the plane was a four-seater Rockwell International light plane and the pilot's family was from Brisbane.

"I understand it was a joy flight and it was pre-arranged," he said.

"There was a number of family of the pilot that were at the Redcliffe aerodrome at the time of the accident."

'Deeply traumatised'

He said the pilot's family were "deeply traumatised, as you would expect".

"We don't believe the pilot was related to the other passengers," he said.

Inspector White said shortly after take-off, the aircraft was seen to disappear behind mangroves. 

He said another aircraft in the area found the plane upturned in shallow water near the mangroves. 

The plane took off from Redcliffe Airport on Sunday morning. (ABC News: Stephanie Zillman)

Queensland Police Commissioner Katarina Carroll said it was a challenging operation.

"The plane is in a very, very difficult position in the wetland area and we have currently got police and divers [in] that area," she said on Sunday afternoon.

Australian Transport Safety Bureau Chief Commissioner Angus Mitchell said the organisation was working with Queensland police in the investigation.

"Early reports are that [the crash] was not long after take-off, but we'll need to confirm that with air traffic control," he said.

"Equally anything we can get from the aircraft itself, any types of recorders that may have been aboard the aircraft and any other information, such as witnesses, to confirm exactly what stage of flight [the crash happened]."

Mr Mitchell said a preliminary report into the crash would be completed in about eight weeks' time.