The trees have been marked for removal to make way for a 12.5 km highway upgrade.
More than 100 members of the Victorian Trades Hall Council have joined traditional owners and hundreds of activists at the Djab Wurrung Embassy as they rally to save a number of 800-year-old sacred Indigenous trees from destruction.
The council, which represents 40 unions and more than 400,000 members in Victoria, arrived at the site along Victoria’s Western Highway on Saturday afternoon amid fears the camp will be evicted on Monday - four days after the original deadline for eviction passed.
Victorian government plans to undertake a safety upgrade of the highway, which connects Melbourne to Adelaide, have put the trees in the firing line despite sustained objection from the land’s traditional owners.
If Major Road Projects Victoria (MRPV) does proceed with the eviction on Monday, it would coincide with the coronial inquest into Tanya Day's death in custody, which activists fear could result in fewer people at the camp.
"We’ve been standing here peacefully, stamping our spiritual authority on our country for 15 months. To have our union brothers and sisters behind us only strengthens our position," Embassy representative Amanda Mohamet said on Saturday.
The trees are marked for removal to make way for the 12.5 km highway upgrade, between Buangor and Ararat, that has been approved by the federal government.
In March, the Trades Hall Council passed a unanimous motion to stand with the Djab Wurrung community and their campaign to stop "the removal and destruction of important sacred trees threatened by VicRoads' planned Western Highway extension".
"We acknowledge their staunch and ongoing resistance to this attack and their identity and culture," the motion read.
"We call on VicRoads and the government to work with their community to urgently resolve this issue and stand ready to take solidarity action if this fails to occur."
An MRPV spokesperson told SBS News last week that they had all "necessary permissions" to start the work and they were ready to do so.
"Too many people have lost their lives on this road - there have been more than 100 crashes and 11 fatalities on the Western Highway between Ballarat and Stawell in recent years," they said.
"[The] western Victorian community has waited for this upgrade."
On Friday, former Victorian Greens MP Lidia Thorpe, who has been a long-time advocate for the trees' protection, told SBS News that the protesters were "prepared for anything".
"This isn't about you know we don't want people to be hurt or arrested or sent to jail. This is about having a peaceful respectful protest and maintaining the protection of this significant site," Ms Thorpe, who was the first Indigenous woman elected to Victorian Parliament, said.
The Victorian Labor government maintains that it worked with the local traditional owners over many years in developing the plans for the safety upgrade, a claim disputed by the Djab Wurrung people.
“The union movement understands what struggle is, right now we have no justice on our country. We stand proud of all our mobs right across this beautiful continent, all over the landscape and we stand united with their struggles and their wars," Ms Mohamet said.
“We’re asking for [Victorian Premier] Daniel Andrews to follow this demonstration from the unions, to come and show his respect on our country, cancel the eviction notice and conduct an open dialogue with our First Nations People.”
A Victorian government spokesperson told SBS News that they "have all necessary heritage permissions" to begin work on the safety upgrade.