Speaking in Latrobe over the weeknd, Premier Will Hodgman said the messages amounted to public property being “defaced”.

“What we’ve done is seek an understanding of the circumstances here, how we might avert this sort of thing happening, because I don’t think Tasmanians like seeing our ambulances defaced,” he said.

But the state secretary of the Health and Community Services Union, Tim Jacobson, said workers were undertaking the action because it was one of the few safe and lawful protests available to them.

“The extent to which ambulance paramedics in particular can take industrial action, and force the government to take a reasonable position, is effected by their commitment to provide emergency services,” he said.

Mr Jacobson said an in-principle agreement pay deal had been made in February this year, but the government since backed away.

He also said the current offer was inadequate, and at six percent over three years, meant ambulance workers weren’t really getting a rise.

“Every paramedic and every ambulance worker knows for the last two years they haven’t received an annual wage increase at all,” he said.

Some pundits believe a similar pay dispute and sign writing campaign in Victoria became a factor in the 2014 election result that toppled a first term conservative government.

But Mr Hodgman says he isn’t worried.

“I’m all for robust democratic process,” he said. “I like these debates to be had in a way where people are honest about what’s happening.”

Despite those comments, Mr Jacobson remains confident a deal will be struck soon.

“The minister has made some reasonably positive comments over the last few days and we’re hopeful the’ll result in us being able to get to the point where able to get this dispute resolved,” he said.