The 134-year boathouse at the Botanic Gardens Southport could be torn down after reports that the roof is close to collapse.
Botanic Gardens Boats & Trains, which operates from the boathouse, has had its lease withdrawn by Sefton Council, which has cordoned off the area.
A Botanic Gardens Action Group representative said: "The boathouse building is in danger of falling down so it will have to be pulled down and completely rebuilt.
"It will have to be replaced exactly as it was but with the council's finances as they are, we don't know when this will take place.
"It's sad to see the boathouse in this state but it's the result of a lack of maintenance."
Boats have been a feature on the Botanic Gardens Southport's lake since it opened in 1875 when they were operated by the local fishermen as a source of extra income.
A Sefton Council representative said: "We are currently looking at the boating facilities at the gardens with the view of re-letting this concession."