Several people injured in seaplane crash off Rottnest Island

Up to six people have been injured after a seaplane crashed off the coast of Rottnest Island on Tuesday.

Water Police and several private boats rushed to the scene after the privately owned aircraft crashed into waters near Thompson Bay just after 4pm.

Two RAC rescue helicopters have been dispatched to the Island, with as many as six people understood to have been injured in the crash.

WAtoday understands at least two women, both in their 40s, have sustained serious injuries.

WA Police said it was not yet clear how many people were on board the aircraft.

The aftermath of the crash was captured on video by several commuters on board the Rottnest ferry, with images of the plane sinking.

More to come.