Former Nationals leader Brendon Grylls says mining activity in the Pilbara has reached the point where any expansion could come at an unjustifiable cost to the local community.
Mr Grylls, the architect of the Royalties for Regions scheme which has funnelled $4 billion to the bush since 2008, surprised many with his remarks at a Port Hedland Chamber of Commerce function last week.
In a thinly veiled swipe at major employer BHP Billiton, Mr Grylls, an ardent pro-development politician, said: "I'm starting to say 'leave it in the ground. Leave it to another company that might be able to do it a bit better'."
Mr Grylls spoke of the company's resistance to a proposed marina at Port Hedland's West End, which the miner wants to be moved 6km out of town, away from the port's shipping channel.
The Pilbara MP called into question industry aspirations to increase shipping movement out of Port Hedland from 300 million tonnes a year to 500 million tonnes, saying that would generate more dust.
"Sir Charles Court said there needed to be a coexistence between community and industry and if you couldn't find that coexistence, then the very justification for that economic activity should be called into question," he said.
"I think that's where we are today.
"Someone needs to explain to me the social dividend of having 500 million tonnes leaving the channel instead of 300 million tonnes if the end result is an abandoned West End and a whole heap of operational workers in camps, because I'll say there's none."
Opposition Leader Mark McGowan said Mr Grylls had become "anti-mining".
Chamber of Minerals and Energy chief executive Reg Howard-Smith said mining royalties accounted for 25 per cent of income in the May Budget.