Thieves have targeted community firefighting equipment, with authorities labelling the incident "disgraceful behaviour".
A trailer on Hodge Street, Glenroy, was forced open Thursday night or Friday morning.
Two portable water pumps and fuel was stolen, which Superintendent Stewart Alexander said was vital equipment..
"We've got a team of trained local residents who do a lot of bushfire preparation work and do blacking out after fires have passed to free up firefighters," he said.
"They're critical for bushfire preparation activity and their local knowledge is very important to us.
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"It's a real shame somebody's taken it upon themselves to steal this very important equipment.
"It's disgraceful behaviour."
Superintendent Alexander said such thefts were rare for the fire service.
CFA and Rural Fire Service brigades have been targeted by thieves in outlying areas in the region.
He urged people to call police or Crime Stoppers with information, with members of the public urged to keep an eye out for the stolen items.