The two Boeing 737 NG Wedgetail airborne early warning and control aircraft will operate from Williamtown RAAF Base as part of No 2 Squadron, and give Australia's air defence an edge.

The aircraft arrived at Williamtown yesterday under the watchful gaze of Wedgetail program manager Air Vice-Marshal Chris Deeble.

"Taking delivery is a step in the process on the way to acceptance into service in March next year," he said.

Air, support and maintenance crews will spend the time between now and then training on the craft.

Once fully operational, the aircraft will require the support of as many as 200 personnel at the base.

The RAAF will eventually acquire six of the aircraft at a cost of just over $4 billion, which includes hardware, development, testing and systems integration, putting the overall cost of each aircraft at just under $700 million.

The Wedgetail aircraft, which houses sophisticated radar and surveillance technology, can locate airborne and ground-based threats for border protection.

"We can also use it to support customs and other civilian agencies," Air Vice-Marshal Deeble said.

The aircraft suffered a number of setbacks during development and testing and was previously slated for delivery in 2006.

Fears that the project may be further delayed were raised as recently as November 2008 when doubts about the Multi-role Electronically Scanned Array (MESA) radar system were raised.

"We are the first customer and inherent in that is some technical problems," Air Vice-Marshal Deeble said.

"Development, test and evaluation are still ongoing with many hurdles still to be overcome."

The Wedgetail is the first aircraft to use the new radar system that operates on electronic scanning so does not revolve as conventional arrays do.