The shedding of 39 jobs at Launceston's Boag's Brewery has come as a shock, the United Voice union says.
Parent company Lion said it was making the changes to improve efficiency in its brewing network.
The Boag's brands will still be fully brewed in Launceston but various national brands will move interstate.
According to Company spokeswoman Leela Gantman, the market had faced a challenging time and added brewing costs in Tasmania had also been a factor.
"We've done this off the back of some very challenging years in the beer market and the need to ensure our operations both nationally and in Tasmania are sustainable," Gantman said.
"Certainly the rate of decline of beer production has been sharper than originally anticipated, so this has put our entire brewery network under pressure."
United Voice secretary Jannette Armstrong said the decision came as a surprise and was "devastating".
"This is going to have a massive impact, particularly [in] Launceston which is already feeling the hurt of unemployment," she said.
"It is very difficult to find a job at the moment, especially in the Launceston area, so it will be a very, very distressing time for those workers and for their families.
"Last year they laid off a whole heap of casuals and they have been talking about the reduced beer market across Australia, but in terms of any indication they were going to be cutting more jobs [that] was an absolute shock and we're disappointed there wasn't more notice and greater consultation."