Police are investigating an "unprovoked verbal assault" on a firefighter which held him up on his way to a callout.
The volunteer firefighter was accosted on January 11 while responding to a callout in Russell.
A police spokeswoman said the firefighter was on foot in Matauwhi Rd when he was approached by a man "behaving oddly".
"The male abused the firefighter in an unprovoked verbal assault, and refused to let him pass," she said.
"It was only when the firefighter explained he was responding to a fire call that he was allowed to continue, but the male then followed him to the Russell Fire Station, where fellow officers intervened."
Police say the man left the area a short time later, having threatened that he would return with a friend.
"Witnesses have been spoken to and positive enquiries are continuing to locate the male involved," the police spokeswoman said.
"Police are confident of a swift and successful resolution to this matter."
It is not the only recent incident in which a firefighter has copped abuse on the job.
At the start of December last year, two firefighters suffered bloody noses while trying to break up a brawl at a crash at Waihi Beach. A 17-year-old was arrested over the matter.
Last year more than 2300 abusive altercations, including assault, were reported by ambulance officers by mid-December.
Meanwhile, police officers reported 346 assaults in 2017 and reported more than 200 assaults by September last year.