WA is likely to substantially increase the rate of drug testing of drivers, despite the high cost of the tests, the state's road safety minister has said.

Victorian Nationals MP Darren Chester has called for the Federal Government to fund the tests.

He said the high cost, which can be up to $600, is limiting the ability of some states to crack down on the growing problem of drug-affected drivers.

But WA Police and Road Safety Minister Liza Harvey said the cost was not a restriction in WA, with tests funded through the specially-dedicated Road Trauma Trust Account.

"Other states don't have that arrangement with their penalty infringements going into road safety initiatives, so I guess we're in a different scenario," she said.

In Western Australia, 100 per cent of money raised from speed camera infringements is channelled into the Road Trauma Trust Account, and must only be used for road safety initiatives.

The WA State Government has been criticised for not spending the money in the account.

Despite a forecast record $111 million spent on road safety this year, budget papers showed the money held in the account would rise from $75 million to $80 million during that period.

In June, a state parliamentary committee recommended WA Police dramatically increase the number of drivers being tested for drugs.

The committee found the number of drivers being drug tested on WA roads was well below other states, and recommended a six-fold increase to 90,000 roadside tests a year.

The State Government is currently implementing the recommendations of the wide-ranging Browne review into road safety, but Mrs Harvey said she expected the Government would fund a significant increase in drug testing.

"Yes, we will be, and that's certainly one of the areas we'll be looking at," she said.

While Mrs Harvey said the cost of tests was not a limitation in WA, she would accept federal funding if it was available.

"We would always welcome that and we could use the money we are currently using to fund the drug tests to fund other initiatives," she said.