Intake Bridge, which crosses Brampton Canal between Lundhill and Cortonwood, was targeted by vandals over the weekend.
The damage has led to a handrail being separated completely from the bridge deck.
Coun Chris Lamb, cabinet spokesperson for environment and transport, told the Chronicle a structural engineer was now needed to assess whether it can be repaired.
“It’s incredibly frustrating that Intake Bridge over Brampton Canal has been badly vandalised,” he said.
“One bearer and handrail have been separated from the bridge deck completely.
“Our rights of way team were informed about this on Saturday afternoon.
“They sent an emergency team out to put up temporary signs and measures to prevent access to help keep people safe.
“Our ranger team went out again first thing on Monday to install temporary fencing on both sides of the bridge and on the towpath.
“An emergency closure order has been put in place for the footpath and more formal signs have been put up, along with more signs further away from the bridge to warn people.
“Local volunteers and landowners are helping us keep an eye on the fencing to make sure the site remains secure.
“We are going to need a structural engineer to assess the bridge to find out whether it can be repaired or needs to be replaced.
“A diversion using local roads will be in place until this investigation and any repair or replacement work can be completed.
“We thank regular users of this bridge for their patience and understanding, and urge anyone with information about this vandalism to report it to South Yorkshire Police.”
Wombwell Coun James Higginbottom said: "I am deeply concerned to see the damage done to Intake Bridge on the Wombwell Canal.
“This is a popular route for cyclists and walkers and it is disappointing that it will be out of action because of this damage.
"I’ll be working very closely with Barnsley Council officers to ensure this bridge is repaired and reopened as a matter of urgency."