Use of the cameras stopped late last year though the hard-drives remained intact.
The woman said she usually changed into and out of her uniform at home because she preferred to wash it separately following a cancer health scare.
However, following a training evening on June 20, she says was ordered to change at the station, and told uniforms could no longer be taken off site.
Despite protesting, she disrobed alone in the usual area, in front of lockers in the engine bay, where the cameras were pointing.
But she did not know the cameras were back in operation, recording the event.
The woman said she was only wearing a singlet and tights under the uniform.
"My breasts would have been exposed or partially exposed when I removed my clothing," she said in the complaint to police.
New Zealand Fire Service fire region manager Kerry Gregory said the cameras were reactivated at the request of officer in charge Maurie Doughty "on or around June 20" because of fresh concerns over missing gloves and boots.
Gregory said signage used in 2015 was re-installed at the same time.
However, Gregory admitted the brigade was not informed because they were the target of the surveillance.
"Brigade members may potentially have been involved in the removal of items from the station without authorisation."
Recordings confirmed the unauthorised removal of personal protective equipment, he said.
There was also footage of 20 firefighters, including two women, getting into and out of their gear, but Gregory said there were no cameras pointing at locations where people would "normally expect the right to privacy", including toilets and changing rooms.
When it was pointed out there are no changing rooms at Mangawhai station, he said firefighters could get changed in the toilet.
The cameras captured the main appliance bay which was an open area and visible from the adjacent road when the bay door was up, Gregory said.
Footage recorded since June 20 had been viewed during an investigation into the removal of equipment from the station, he said.
Footage was accessible by the brigade's volunteer support officer and Doughty, he said, and a firefighter who knew how to operate the system.
The woman complained to the New Zealand Fire Service about the incident when she resigned in October.
Last week she laid a complaint with Mangawhai Police against the volunteer fire brigade's chief fire officer Wipari Henwood, Doughty and second in charge Robert Leslie for "making visual recordings without the knowledge or consent of myself".
The woman said she was humiliated at being filmed and told police she did not know if her superiors watched her getting undressed.
Police would not confirm receipt of the complaint.
A spokesman from the Office of the Privacy Commissioner said agencies should tell people when cameras were in use. However, there were exceptions.
"One of these circumstances is when telling the individuals would get in the way of the purpose of collection. Informing thieves that they were being recorded would have rendered the camera pointless."
He added that generally when information was publicly available, for example if someone could view firefighters changing from the street, then there was usually not a privacy issue.
Her complaint comes a year after allegations of bullying within the brigade made headlines and divided the small Northland town.
The Fire Service dismissed an earlier complaint from the woman about bullying within the brigade.
That complaint in August was dismissed by Henwood, also the Fire Service's Whangarei assistant area manager, because the woman did not respond to further questions in time.
