CFMEU ACT has urged the Australian National University (ANU) to abandon its threats to evict the student encampment peacefully protesting Israel's war in Gaza.
ANU management has directed students participating in the encampment to vacate and remove all personal belongings by the end of Friday.
CFMEU ACT Secretary Zach Smith said the union was behind students at the encampment.
"ANU's bosses need to take a good hard look at themselves for this heavy-handed ultimatum levelled at students simply exercising their democratic right to peacefully protest," he said.
"Peaceful protest is a cornerstone of any healthy democracy and this ridiculous attempt to stifle free speech must be rejected outright.
"Canberrans are proud our city is a place where people from all walks of life peacefully protest for change, whether that's at local, federal or international level.
"We also stand in solidarity with all our NTEU comrades who are supporting the student encampment at ANU.
"The CFMEU has a proud record of standing up for peace and the truly horrific situation in the Middle East is no exception.
"We reiterate our call for an immediate permanent ceasefire, the release of all hostages and of all Palestinians illegally held as political prisoners in Israel, and an end to the blockade of Gaza."