A proposed tram bridge will prevent large boats and yachts from entering Docklands’ Yarra’s Edge marina, causing property prices in the ritzy locale to drop, residents say.

The bridge is part of a state government draft proposal for the new Fishermans Bend precinct, and, if approved, will extend the tram line at Collins Street, connecting Docklands with the new suburb.

A group of Yarra’s Edge locals are holding a rally on Tuesday evening, at which Footy Show host and local resident Sam Newman will speak, to pressure the government to consider an alternative to the tram bridge.

Resident Keith Sutherland said the group plans to bring a class action lawsuit against the government should the bridge plan go ahead.

“Most of us, including myself, bought into the area with the ability to look down at the marina seeing all these large yachts and boats that come in,” Mr Sutherland said.

Many of the 2500 Yarra’s Edge residents also owned yachts which they berthed in the marina, and Mr Sutherland said they were worried the tram bridge could cut their property values by up to $100,000.

He said he understood there was a certain amount of risk when buying property for the view – but that he did not expect it would be a factor at Yarra’s Edge.

“There’s an open marina, a river and basically you buy there not expecting anything to be changed,” he said.

Fishermans Bend is expected to house 80,000 residents along with 80,000 jobs. The project is proposed to be built in stages, with the tram bridge slated to be completed by 2025. Also proposed is an underground rail connection and two off-road cycling paths.

Mr Sutherland said instead of the tram bridge, he would like to see an immersed tube – a tunnel which is pre-built in sections and then submerged in the river – to take on the trams to Fishermans Bend.

“The alternate we’ve come up with is an immersed tube which would run down trams 86 and tram 70 – they are the least utilised trams,” he said. “The current proposal is to use the Collins Street tram which is already at maximum capacity.”

Mr Sutherland said he has consulted experts about the possibility of an immersed tube, but they were unable to comment on it without planning specifications.

“I’m not an engineer, I can’t offer any technical support, and that’s what I want the government to look at and offer their support to have a look at it.”

Up to 300 people are expected at the rally on Tuesday, and Mr Sutherland said most of the residents he had spoken to did not want the tram bridge.

He said if it went ahead, it would be costly for the government.

“If they have to spend $300 million to $500 million paying out a class action – that’s well and truly going to cover the cost of the immersed tube,” he said. “This could be the largest class action in Victoria if it goes ahead – but we’re wanting sanity to prevail.”

Transport for Victoria considered a number of routes for the tram connection to Fishermans Bend, including a tunnel option, a government spokeswoman said.

“The government is currently considering feedback provided on the draft Fishermans Bend Framework,” the spokeswoman said.