By Tiffany Fox

A seaplane has crashed into the water while taking off at Rottnest Island, sparking a rescue operation by water police and civilian vessels.

Emergency services were called to the incident about 4pm on Tuesday after the sea plane flipped during take off and crashed into the water near the popular holiday destination, 30km west of Perth.

WA Police Commissioner Col Blanch said the plane was believed to have hit Phillip Rock at the entrance to Thomson Bay.

He said four people had been recovered from the wreck and were being treated for injuries. At least two women are believed to be in a serious condition.

Partial debris from the Cessna 208 was towed the Rottnest Island army jetty.

Boat skipper Tony Brooke, from Sorrento, said he was moored at Thomson Bay when he heard commotion in the water.

“I could see that the tail was out of the water and most of the plane seemed to be submerged,” Mr Brooke said.

“Later it appeared it had rotated and one of the wings was out of the water and the tail had disappeared.”

Witnesses said they saw the plane beginning to lift off the water when it appear to bank sharply before tipping over.