The largest ship ever built for the Royal Australian Navy is undergoing final builder sea trials, which includes testing of combat and communication systems.

BAE Systems, builder of the NUSHIP Canberra, a landing helicopter dock ship, said the trials were taking place until the end of the month off the coast of New South Wales.

"This is the last major element of a very complex and comprehensive test program to prove the capabilities of the ship and its systems prior to delivery to our customer," said Bill Saltzer, director of BAE Systems Maritime.

"Getting this ship to this stage has been a collaborative effort between BAE Systems and the Defense Materiel Organization. Our two project teams have worked closely throughout the project and now we are in the home stretch."

The NUSHIP Canberra, the first of its class, displaces 30,300 tons. It is more than 757 feet long and 105 feet in the beam. It has a range of 9,000 nautical miles and a maximum speed of more than 20 knots.

Its vehicle capacity tops 100 vehicles. More than 1,000 troops can be carried by the ship, as well as helicopters for transporting them to shore.

A second Canberra-class ship, the NUSHIP Adelaide, is under construction and is expected to enter sea trials next year.

Main sub-contractors of the NUSHIP program are Navantia, which conducts platform design and hull construction in Spain; SAAB, the combat system integrator; and L3 for the internal and external communications systems.