The commemorative structure was built for employees of the former Caterpillar plant in Tannochside, near Uddingston, North Lanarkshire, who staged a 103-day occupation in 1987 to try and save their jobs.
The memorial, which was funded by sponsorship, the trade union movement and North Lanarkshire Council, was unveiled earlier this year.
However, in the early hours of Saturday, thugs wrecked the artwork, which was set up just 100 yards from where the factory stood.
Members of the community spoke of their shock and sadness at the mindless act.
North Lanarkshire Councillor Bob Burrows, who represents the wider Viewpark area, is a former Caterpillar shop steward and one of the group behind the campaign to create the memorial.
He said: "I could have wept when I saw the damage.
"To see such an impressive community memorial wantonly destroyed less than 11 weeks from its unveiling was truly heartbreaking. But we refuse to be beaten.
"My phone hasn't stopped ringing since the damage was discovered at the weekend and it's clear that while the Caterpillar factory is long gone, the fighting spirit which saw 1200 men and women occupy the plant for three months lives on."
Mr Burrows said it might cost as much as £10,000 to replace it.
He added: "But even if it takes another two years fund-raising, the memorial will be replaced."
A Police Scotland spokeswoman said officers launched a probe when the vandalism was reported to them on Saturday morning.
She added: "Inquiries are ongoing into who is responsible. No arrests have been made."
The sit-in was held after the company, which had originally announced a multimillion investment, decided that the plant was to shut down. It delayed the closure but the plant shut on October 28, 1987.