Women are being warned to watch for people filming up their skirts after the arrest of four men in Christchurch who police say preyed on Christmas shoppers.
Detective Sergeant Craig Farrant said police had arrested the men, aged between 30 and 55, over separate incidents in Eastgate shopping mall, Westfield Riccarton and the Eastgate Warehouse over the last three weeks.
"Police have received reports of a number of instances where males have been seen covertly filming under females' skirts using a range of devices - from cellphones to covert camera systems," Mr Farrant said.
The arrests of the four men have resulted in "a large number of charges, which are still being collated", Mr Farrant said.
They are yet to appear in court.
Police said in a separate case, a teacher had been charged in relation to an incident at Westfield Riccarton last month.
"In all these cases, the victims are unknown to the offenders. Our concern is that once these images are captured there is no control over the potential use or distribution of the material," Mr Farrant said.
"It's extremely disappointing that we have to issue such warnings - but we do encourage women to remain vigilant while climbing stairs, using escalators or standing in close confined spaces with others, where they may be susceptible to such activity.
"This type of offending is taken extremely seriously and anyone caught offending in this manner can expect swift action from the police, including arrest and court appearance."
Police said they were urging vigilance as large crowds filled the city's shopping centres and malls.
Mr Farrant said anyone who saw suspicious activity should contact police or mall management immediately.
Anyone with information should call Christchurch Police on 03 363 7400 or Crime Stoppers on 0800 555 111.