Western Australia's police commissioner has questioned Premier Colin Barnett's claim that drug use is rife in the state because of high incomes.
Premier Colin Barnett made the assertion when asked about high drug usage rates despite his party's hardline stance at the leaders election debate on Wednesday night.
"The reason drugs are high here is because incomes are high, that's a reality," he said.
Police commissioner Karl O'Callaghan said it was an unsubstantiated view that began from the idea that workers with high disposal income during the mining boom were buying and using drugs.
"I think it's an interpretation. There is no evidence or data that proves that is the case," he told 6PR radio.
"Why (usage) hasn't changed with a change in the economy, I don't know. Perhaps people are hooked now and they have no choice."
He said there was a range of other factors for high drug use, such as WA's vast 20,000km coast line which he described as a "soft border".
Mr Barnett defended his comments on Thursday, saying the state had been targeted by drug syndicates when wages were high during the mining and construction boom and this had contributed to meth usage rates becoming the nation's highest.
"Attention has been drawn to that by magistrates, by health officials and so on, so I'm not saying anything new - it's just one of the factors," he told reporters.
Addiction to the drug ice and associated violent crime is a major problem in WA, which had the biggest number of per capita users of it in a 2013 National Drug Strategy household survey.
Scientific analysis of the state's sewage last year found enough traces of the metabolised drug to point to residents having a $2 billion a year, 57,000 hit a day habit.