Whangarei police are photographing window washers and getting their details to build a picture of who they are and the intersections they are working.
It comes as police expressed concern at the lack of motorists reporting assaults, vehicle damage and sexualised behaviour by window washers around the city.
Teams of washers, sometimes as many as 15, are regulars at the intersections of State Highway 1 and Rewa Rewa Rd, Maunu Rd and SH14, and Western Hills Dr and Kamo Rd.
There has been a surge of comments complaining about their actions on social media about the window washers, especially on the Facebook page Stop the Window Washers Whangarei, but police are concerned at the lack of official reports to them.
Area prevention manager Senior Sergeant John Fagan said the state highway network route through Whangarei was not under the control of the Whangarei District Council so was not subject to the local bylaw.
Instead the intersections were controlled by the NZ Transport Agency.
Mr Fagan said it meant police had no power to remove window washers from these intersections unless they committed a criminal offence.
"We are interested if these window washers are committing offences of assault or damaging property or are acting inappropriately towards female motorists in particular," he said.
"Our advice is, make it very clear you don't want your windscreen cleaned, do not pay them or engage in conversation with them. Please report any criminal offending to police."
Over the past two weeks police have been photographing window washers and obtaining details under the Land Transport Act which allows officers to get details of people on roads whether they were in a vehicle or not.
"If people give us a good description with their complaint we could possibly match them up," Mr Fagan said.
While he could not say how many times a day police received calls about the behaviour of washers he said it was "more than just a few".
If motorists believed a crime had been committed he recommended they ring 111 immediately with as many details as possible. Otherwise if people had photos of the offenders they should make a report at the nearest police station.
Yesterday a complaint was taken about a washer at the Western Hills Dr and Kamo Rd intersection who had stepped between a car and the trailer it was towing.
The intersections on the highways come under the jurisdiction of the NZ Transport Agency, while other intersections are subject to a Whangarei District Council bylaw and people can be fined $500 if they refuse to move after being asked by police.
Last December NZTA's Auckland Highway manager Brett Gliddon said there were no specific rules to prevent window washers on state highways outside of general road rules, and the creation of a bylaw would be necessary within specific areas.
NZTA is investigating whether a bylaw in Whangarei was appropriate.
"We are investigating installing information signs to warn people about the safety issues caused by window washers," Mr Gliddon said.
"We believe from anecdotal feedback from our team that the issue is causing real concern within the Whangarei community which is why we're working on several avenues to ease the situation."
Yesterday the Northern Advocate asked NZTA if any action was being taken in relation to the influx of window washers.
In a written response a spokeswoman said: "There's no update on this at the moment."