Up to 10 military planes, four civil jets and nine ships will assist in today's search for missing Malaysia Airlines flight MH370.

The Australian Maritime Safety Authority has determined a search area of about 217,000 square kilometres, 1700 kilometres north west of Perth.

Today's search area will focus on three areas within the same vicinity.

The first aircraft will depart for the search area at 6am Western Standard Time (WST).

A total of 26 State Emergency Service (SES) volunteers from Western Australia, New South Wales and Victoria will work as air observers on three of the civil aircraft. The other civil aircraft will operate as a communications relay.

The weather forecast for today's search is fair, with visibility approximately 10 kilometres and a cloud base between 1000 and 2000 feet.

The Australian Transport Safety Bureau continues to refine the area where the aircraft entered the water based on continuing ground-breaking and multi-disciplinary technical analysis of satellite communication and aircraft performance, passed from the international air crash investigative team comprising analysts from Malaysia, the United States, the UK, China and Australia.