Vandals set fire to the wooden walkway which was created in Popeye’s Park near Lincluden Community Centre two years ago, after an eight-year fund-raising campaign.
North West Dumfries Councillor Andy Ferguson said: “It’s a sad indictment that this could be allowed to happen.
“We’ll need to await the outcome of the police enquiry before making further comment, but it’s a sad day because a lot of time and effort from the community went into that.”
And he added: “The losers here are the community – they’ve lost a valuable asset for leisure which really helped to brighten up the neighbourhood.”
The bridge spanning an area of water is understood to have caught on fire some time between last Tuesday evening and Wednesday morning.
A spokesman for Police Scotland said: “Sadly it’s just absolute wanton vandalism – that’s all it appears to be.
“It’s not harming people, so why anybody would want to set fire to it is beyond us.
“And we’d ask anybody that has any information or may know who carried this out to please get in touch with us, because it’s probably just vandalism at its worst.”
He added: “It’s affecting a community area that young people use, and the elderly people take a wander through there and have a look at the pond, so it’s affecting a whole community.”
Anybody with information about the incident is asked to contact police on the non-emergency 101 number.