WA Labor MP Vince Catania last night quit the party to join the Nationals, citing problems with Labor's direction and a desire to see the WA Nationals' Royalties for Regions policy implemented.

"This is the way to deliver what my electorate wants," Mr Catania told WA Today.

"The only way regional WA can continue to get its fair share of funding is to ensure the National Party has the balance of power. It's the only way to keep the bastards honest, so to speak."

Mr Truss said the people of regional Australia were appalled by Labor Party policy being run from the capital cities by people who treated the regions with contempt.

"I can only imagine Mr Catania’s decision, given his family background and commitment to Labor ideals, must have been very hard for him," Mr Truss said.

"But that said, you cannot continue living a lie – in politics you must stand up for what you believe in.

"Federally, Kevin Rudd cut more than $1 billion from the regions in his first Budget.

"In the second, countless billions more were slashed, all the while creating a monstrous Federal debt that will take decades to pay off.

"The three Labor frontbenchers charged with policy and programs for Australia’s regions live in adjacent inner-Sydney seats.

"Labor's attitude to the regions is dismissive, destructive and sneering, and they spend most of their time in Parliament belittling the achievements of regional people.

"Mr Catania's decision is an enormous credit to the performance of the WA Nationals led by Brendon Grylls.

"Their Royalties for the Regions deal with the Liberal Party has been very successful and in government they have knuckled down to the complex and demanding job of doing the right thing by all West Australians in tough economic times."

Mr Truss said he would "happily welcome any Federal Labor MPs into the Nationals fold if they were prepared to jump ship".