Vic volunteer firies vow to back PM

Darcy Zaina always wanted to be a volunteer firefighter.

"I just reckon it's fun and I like being there for other people," the teenager told AAP on Thursday.

But the increasingly bitter battle between Victorian volunteer and career firefighters is taking its toll on her family.

Now her dad Jon is having second thoughts about letting his daughter work under changed union conditions.

"I don't think I would encourage her to take it on because it's unfair," he said.

Mr Zaina was once a Labor voter but now he's changed his mind, and the Victorian volunteer firefighter believes about half a million votes in the state could go to the coalition in the politically-charged stoush.

"There would not be a volunteer I imagine that would not vote for Liberal now - I guarantee it."

Mr Zaina said the entire state was in uproar, with CFA members set to rally for the coalition in the election.

That was the message he relayed to Prime Minister Malcolm Turnbull during a meeting with the local CFA branch in the Liberal-held marginal seat of Corangamite on Thursday.

Mr Turnbull ramped up his language in the dispute, warning volunteers they were in the firing line of unions.

The government had won the fight against the road safety tribunal but unions wouldn't stop there.

"You're next in their targets," he told the gathering.

Mr Turnbull said he normally would not make a political speech to volunteer groups such as the CFA, but there was a clear choice at the July 2 election against militant unionism.

He used the visit to reaffirm the coalition's pledge to amend the Fair Work Act to ensure volunteers have the freedom to carry out their duties.

Labor leader Bill Shorten criticised Mr Turnbull for grandstanding on a state issue. "I have no doubt Mr Turnbull wants to use volunteers as political pawns in his pursuit of power," he told reporters in Adelaide.