The pedestrian bridge over the weir in Keynsham Memorial Park has been closed today by Bath & North East Somerset Council.
During this week the council found that the beams of the bridge have decayed and further investigations are needed.
Barriers have been put up at both sides of the bridge and the council has signposted alternative routes for pedestrians.
Dine Romero, Leader of B&NES Council, said: “The safety of residents is our priority, so we have made the decision to close the bridge until further notice while we fully investigate its condition and decide the next steps.
“We apologise for any inconvenience caused and hope that people understand why we have taken this urgent action.”
The bridge is more than 25 years old and is known as a Glulam bridge due to its method of construction from glued laminated timber.
At this early stage, the council says it does not have a timescale for when the bridge will be reopened to the public.