Two of the McGowan Government's key budget measures are in serious danger of being blocked by Parliament, with Treasurer Ben Wyatt now relying on Liberal Party support to avoid an $800 million black hole.

The decision of five key crossbenchers to oppose increases to gold royalties and payroll tax means the measures will be blocked by State Parliament's Upper House, unless the Liberals vote with the Government.

The Liberals are yet to decide what to do.

But the opposition of the Nationals, One Nation, the Liberal Democrats and the Shooters, Fishers and Farmers leaves the budget measures on shaky ground.

Less than a week after Mr Wyatt's first budget, he now faces the prospect of having to find alternative revenue-raising measures or see his hopes of returning the state to surplus dealt a substantial blow unless he can win Liberal Party support for his plans.

The bloc of five conservative Upper House crossbenchers held discussions about the big business payroll tax increase and gold royalty hike in recent days, deciding there was no way they could support them.

Sorry, this video has expired Your guide to the WA budget 2017

"We just cannot vote for something that is going to cost jobs on a mass scale," One Nation leader Colin Tincknell said.

"If they were paying off the debt then we could debate it, but that money from those two measures … is going to be used for pork-barrelling."

Fears for WA jobs

Shooters, Fishers and Farmers MP Rick Mazza said he was fearful of the economic impact if the payroll tax and gold royalty hikes were implemented.

"The economy is very flat in WA and jobs are very important, so anything that discourages employment is something we would struggle to support," he said.

Liberal Democrat MP Aaron Stonehouse said he was firmly opposed to both measures.

Aaron Stonehouse says he will not support the measures. ( ABC News: Eliza Laschon )

"I pledged that I would never compromise on my principles of limited government, individual liberty and lower taxes and I stand by that pledge," Mr Stonehouse said.

Because Labor is well short of an Upper House majority, both the royalty and tax increases will be voted down without Liberal support — even with the Greens expected to side with the Government.

It is understood there are mixed views within the Liberal Party on how to approach the situation, with fears in some quarters that blocking the budget measures would be a bad look, given accusations of budget mismanagement hurled at the former Barnett government.

But others within the party are understood to feel the party should oppose measures they believe will have a severe impact on jobs and the economy.

Mr Wyatt has previously warned the rejection of those budget measures would mean he would have to hit households harder instead.

Late yesterday, he again urged the Liberals to support the budget measures.

"Please help me get these through so we don't have to look to households to take up an even greater burden," the Treasurer said.

"You have a large amount of expectation from the broader community to respond to the fiscal circumstances."