PM Malcolm Turnbull visits WA shipyard and Darwin pub

Prime Minister Malcolm Turnbull has started the day talking ships in Perth and finished by talking to punters in a pub in Darwin.

At the start of a long day on the campaign trail, Mr Turnbull discussed growth and jobs, declaring a vessel constructed by shipbuilder Austal for the navy of Oman to be awesome.

"Australian jobs, Australian workers, Australian technology building some of the most sophisticated naval vessels in the world right here in Perth," he told reporters.

Mr Turnbull's visit to Austal was his sole WA campaign event.

Notably absent was the state's Liberal premier David Barnett and the Liberal candidate for the seat of Fremantle, Sherry Sufi.

The PM stopped short of disowning Mr Sufi who has argued that legalising same-sex marriage could lead to polygamy.

Mr Turnbull toured Austal production facilities and walked through the brand-new vessel destined for the Omani navy.

He said Austal had constructed 250 vessels with 200 exported.

"This company Austal represents exactly what we are seeking to achieve with our defence industry plan. It sums up the objective of our national economic plan - jobs and growth," he said.

Austal, with its 600-strong workforce will build up to 21 new Pacific patrol boats and maybe later, new offshore patrol vessels for the Australian navy.

It's also just completed a pair of support vessels for the Omani navy and is completing a 72-metre oil rig support vessel for use in the Caspian Sea.

Mr Turnbull announced that the Pacific patrol boats will be made of Australian steel. As each vessel displaces around 100 tonnes, this isn't a huge quantity by shipbuilding standards.

After departing Perth, the prime ministerial VIP aircraft jetted to Darwin, with the first of a number of NT campaign events conducted in a local pub, the Lizard Bar.

This was a mostly sympathetic gathering. After Mr Turnbull bought an ice-cold beer, he parried questions on such topics as jobs and growth, defence spending, resource development in the north and health.

The biggest cheer came when he mentioned the purchase of a $15 million scanner for Darwin hospital.

The occasion wasn't totally friendly - one questioner asked about spending to tackle the ice epidemic, responding to the PM's explanation with: "It's not happening."

Mr Turnbull made a strong indication the government will dump the unpopular backpacker tax, a sore point in the NT which relies on visitors with working visas for casual employment in the hospitality industry.

Under this measure, these workers would have no tax-free threshold and would be taxed on every dollar earned.

"Just watch this space," he said.