United Firefighters Union Tasmanian acting secretary Leigh Hills said he was unsure if members would accept the offer.

"The vote is entirely up to members, it is their decision," Mr Hills said.

"We're disappointed the government hasn't agreed to combine two separate agreements when one of their principles is streamlining.

"We have our firefighters and those who work with Tasmania Fire Service equipment under two agreements when they should be combined under one. We will continue conversations with government around this issue."

Mr Hills said the union also wanted classifications for firefighters updated.

"They are outdated and they don't encompass the specialist skill sets that firefighters in Tasmania have," he said.

"We don't have the specialist units they have interstate so our firefighters take on a whole range of special skills."

The ballot for Tasmania's 348 firefighters to vote on the wage offer closes on Sunday at 5pm.