Fly-in, fly-out (FIFO) workers should be regarded as Australia's "modern day heroes", Western Australia's Premier Colin Barnett says, akin to the men who built the nation-defining Snowy Mountains irrigation scheme.

Mr Barnett made the comment in response to the federal government announcing a clampdown on the 457 visa program for temporary foreign workers, aimed at ensuring Australian workers get first preference for jobs.

While federal Treasurer Wayne Swan says he has "personal evidence" Australians are having trouble finding work in mining and other industries because overseas workers are filling jobs, Mr Barnett has not only stuck up for FIFO workers, but has also said the foreign labour is essential for WA's $237 billion economy.

Hitting back at what he said was a campaign of vilification of the FIFO workforce, Mr Barnett said those people should instead be lauded.

"FIFO workers are modern day heroes," Mr Barnett said in the final week of the state election campaign.

"They do separate from their families, they do put up with some loss of amenity, they work in harsh conditions, for long hours, doing exciting work.

"They are building this state and building this nation. You can draw a parallel with the migrant workers on the Snowy Mountain scheme - these are the modern day heroes of the economic development of Australia.

"They deserve more respect, and not to be treated like some scourge of the earth."

Around two thirds of the workforce employed in the construction of the Snowy Mountains scheme, which was finished in 1974 after 25 years, were immigrant workers originating from over 30 countries.

It is estimated the current FIFO workforce in WA totals 50,000 and is set to rise to 63,000 by 2015.

James Pearson, chief executive of the WA Chamber of Commerce and Industry, said he understood from the immigration department that "something less than one per cent of employers have been abusing the system".

But Immigration Minister Brendan O'Connor rejected expert assessment suggesting only three per cent of temporary worker visas were questionable.

Mr Barnett said rather than clamp down on foreign workers who were willing to come to Australia to fill the positions, the government should be asking why more Australians were not willing to move where the high-paid work was.

"They (457 visas) are essential for WA in particular and we have been a big employer of 457 workers, and they go across a who lot of areas, trades, engineers, a whole scope of works," Mr Barnett said.

"I think it is a pity that in Australia more people with those skills aren't prepared to come to WA and aren't prepared to go into the Pilbara and take on these demanding, challenging, exciting jobs which are highly paid.

"That is one of the weaknesses of the Australian economy."