SA 'can't build a canoe': Leyonhjelm

Picture it - submarines and jet skis, cruising down canals through western Sydney.

It's the vision of Liberal Democrats senator David Leyonhjelm, who used question time in the Senate on Wednesday to spruik the benefits of building warships in western Sydney.

For one thing, the people there aren't as parochial, he says.

And the warships could come in different colours and be powered by nuclear energy.

Most importantly, the delays and cost overruns of the air warfare destroyer saga has shown South Australia has a "dodgy record" when it comes to shipbuilding.

The state "shouldn't be trusted to build a canoe", the senator says.

Defence Minister Marise Payne was grateful for the suggestion but insisted the black livery would be maintained, on account of submarines needing to be capable of camouflage and stealth.

She says the lack of water may also pose a problem.

But Senator Leyonhjelm was full of optimism.

The government could embark on a job creation project building canals through marginal seats from Reid to Lindsay, "to aid in future submarine building projects, including getting them to the sea and providing kids somewhere to race their jet skis".