THE WA National Party's royalties for regions policy is not negotiable and the only temptation that would cause it join forces with another party is unambiguous support of the policy, National leader Brendon Grylls says.

Speaking to Farm Weekly last week during an exclusive interview in the lead up to the September 6 election, Mr Grylls outlined his party's firm position and vision for the future.

He also discussed its plans to extract a better deal for regional WA by winning the balance of power at polling booths.

He said the tighter the election, the better chance he stood of gaining support from the two major parties to spend $700 million a year of State mining windfall on rural infrastructure.

Mr Grylls was adamant he would not trade National Party policies for the deputy premiership.

"Joint-party rooms simply don't work when you are outnumbered by Perth politicians," Mr Grylls said.

"And I have been saying for two years there will be no coalition before or after the election, with anyone.

"If I am offered the deputy premier's job I will say no to it because I know that it is a buy off so I can't get my royalties policy implemented.

"We have been campaigning on that policy for two years.

"The TV ads have been running since the start of the year and I will stay true to my word."

"I will not be backing down.

"We seek the balance of power and that means our vote is needed to pass government legislation, and the only way we will do that is if our royalties plan is implemented.""