Members from Protectors of Public Lands and the Casey-Cardinia-Dandenong branch of the Greens tied a 'stop the chop' banner at a rally next to the tree in Clyde Road last Tuesday.

The oak is slated to be removed in works to widen a section of Clyde Road to four lanes, expected to start as early as this month.

Protectors of Public Lands have been involved in several high-profile campaigns to save trees under threat, including Energy Safe Victoria's plan to lop street trees under power lines, World War I memorial trees in Bacchus Marsh and 550 100-year-old elms in Camperdown.

Secretary Julianne Bell said the tree, known as the Gardiner or Genesis oak, should be on the National Trust's register of significant trees.

"This is our heritage, this is part of Berwick's history."

Ms Bell said she did not accept VicRoads' position that there was no way to save the oak in the upgrade.

"They have been known to modify plans."

Michael Schilling, convener of the Casey-Cardinia-Dandenong branch of the Greens, said local members were strongly in favour of retaining the oak.

"The tree is at least 175 years old. It's part of the DNA of Berwick and to see it cut down would be a real shame."

Former Berwick mayor Syd Pargeter said the tree could stay if a Casey council ruling to remove the pillars of the Genesis gym was upheld.

"There is a way to save the oak. VicRoads needs to be flexible and innovative."

A Clyde Road business owner at the rally, who declined to be named, said he was in favour of the road being widened but the railway level crossing should be grade-separated first.

"Clyde Road is broken, but it won't matter until the crossing goes underground too.

"I don't know how many millions they spent on the traffic lights at the crossing, but they do absolutely nothing."