The farm was being seized for a deputy governor of Zimbabwe's central bank, according to farmers union members.
The shooting on Wilfrieda farm in the Chinhoyi district about 100 km north of Harare marked a serious worsening of tensions in the country and its coalition government amid a sudden renewal of violent incidents led by President Robert Mugabe's security forces and supporters.
It follows the decision by pro-democracy Prime Minister Morgan Tsvangirai two weeks ago to partially disengage from the unity government over Mugabe's refusal to carry out agreed-to democratic reforms.
Two male workers and a woman were in hospital in Harare with severe gunshot wounds inflicted by rubber bullets, doctors there said. Rubber bullets, normally fired by automatic rifles, are legally issued in Zimbabwe only to the armed forces.
A dozen more workers were blasted with shotgun pellets and were treated by doctors in Chinhoyi.
Farm union officials said it was believed to be the first time firearms had been turned on farmers or their labourers since the start in 2000 of Mugabe's campaign to dispossess whites of their farms.
The invaders on Wilfrieda also burnt down half of the workers houses in a bid to force them to leave the farm. Worker Stanford Kunzemutema, who suffered head injuries, said from a doctor's surgery that he and 50 other farm residents were assaulted with wire and sticks from the start of the dawn raid until 2pm.
The violence stopped, he said, when police from a station 10km away arrived several hours after being called. Police did nothing to the attackers, but "took one of us to make a statement," Kunzemutema said.
The Commercial Farmers Union (CFU), whose predominantly white membership has dwindled to about 300 from 5,000 in 2000, has reported repeatedly in recent months on attempts by Edwin Mashiringwani, the deputy governor of the central bank in charge of bank operations and markets, to seize the farm from its owner, Louis Fick.
The CFU said the banker had repeatedly used force to stop Fick's workers from feeding a large herd of pigs, to starve them and make him give up his land.
Kunzemutema said Fick had been in Harare on Thursday and Friday to consult with his lawyer about a renewed stoppage of feeding when two truckloads of over 50 thugs were off-loaded on the farm.
"They said, 'We are taking this farm, you have to get off,' but we refused," he said. "So they started beating us."
He said the workers had tried to resist the attackers.
"We tried to protect ourselves," he said. He described how the attackers produced two shotguns and opened fire on them several times.
"They continued beating us, and they burnt our houses down," he said. "They beat us until 2pm when police came, and the violence stopped."
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