Apple, cherry and stone fruit yields are threatened after temperatures at orchards across the state dipped below zero.
Fruit Growers Tasmania President Tim Reid said the extent of the damage would not be known for several days, but growers faced losing up to half their crops.
"Early estimates I would not be surprised, even at this early stage, if the crop hasn't been reduced by half," Mr Reid said.
"It's soul-destroying ... it's really quite devastating."
The downturn would result in a shorter fruit season, pushing prices up, and could potentially cost jobs in the picking and packaging end of production, he said.
Mr Reid said Fruit Growers Tasmania had not ruled out lobbying the federal government for funding relief once the full impact of the frost was known.
Mr Reid said stone fruit and cherry orchards in the Coal River Valley, north-east of Hobart, were the worst hit last night.
Apricot grower Heather Chong, of Qew Orchards in the Coal River Valley, had been expecting a crop of 700 tonnes this year, netting more than a million dollars.
But the frost has ruined about half that, “The preliminary assessment is about a 50 per cent loss on average, Some varieties will be completely lost, some will be much less," Ms Chong said.
"What can you do? You just feel rather numb I suppose ... and then you have to work out what it means and how bad it is."
Ms Chong said efforts were now focused on protecting the remaining crop from disease caused by rotting fruit.
Orchards in the Huon Valley, the Derwent Valley, at Spreyton, near Devenport, and around the Tamer River, near Launceston, were also affected.
The frost came after a cold blast decimated crops in Victoria's Goulburn Valley last month, costing growers an estimated $80 million.