HMAS Canberra coming together at BAE Williamstown - The Australian

The Royal Australian Navy's new Air Warfare Destroyer. Source: Supplied

THE Gillard Government has given its strongest signal yet that it will build a fourth navy destroyer.

Inspecting the navy's biggest ever ship - the under-construction 28,000 tonne Landing Helicopter Dock, to be named HMAS Canberra - at the BAE Systems Williamstown shipyard in Melbourne yesterday, Defence Minister Stephen Smith said the government was acutely aware of the need to keep ship-building work flowing.

"Not just for our naval and shipyard employees and companies, but generally, and one of the things that we are looking at the moment, is whether there is a capacity for more work to be given to this workshop, to this shipyard, in the Air Warfare Destroyer project," he said.

That is good news for the 1200 employees at the Williamstown yard and for BAE Systems, which has struggled to build some of the early destroyer blocks.

"BAE, to its credit, has substantially enhanced and improved both its technical capacity on this site, but also the work that it is delivering," Mr Smith said.

The government has pledged that the Defence White Paper, due out before the end of 2013, would include a bridging project but it has been reluctant to confirm whether or not that will be a fourth AWD.

Defence Materiel Minister Jason Clare said the government would not repeat past mistakes by allowing the skills base to decline before the new submarine project (12 boats) was up and running in about 2025.

The 12 subs will cost more than $30 billion under the nation's biggest defence project, creating thousands of jobs and work for hundreds of local companies in Adelaide and at yards around the country, including Williamstown.

Meanwhile, work is on track to have the first LHD in navy service by 2014.

The two ships will be the biggest operated by the RAN and their decks will be large enough to carry four Anzac frigates.

Mr Clare said that if Melbourne's Rialto Tower was laid down it would be the same length as the LHD.

"It's also a floating city, this is a ship which can hold over 1000 soldiers, 100 trucks and 12 helicopters, and it's got a hospital that can cater for a town around about the size of Warrnambool, and when powered up can produce enough electricity to power a city the size of Darwin," he said.