The imprisonment of a sexual predator - has prompted Police to urge caution

Aucklander Micah Fala man secretly filmed 22 women and girls with covert cameras.

He's been sentenced to four years in prison, after pleading guilty to 42 charges.

Many victims were recorded as they showered, undressed or used the toilet - including five children.

Detective Inspector Scott Beard says people should be vigilant about the ways technology can be used, for criminal behaviour.