Thieves were targeting cars in New Plymouth's Motoroa and Blagdon areas over the weekend, police say.
Sergeant Bruce Irvine said six cars had been broken into.
''Some have had nothing taken and some have had small stuff taken,'' Mr Irvine said.
He urged the public to lock their vehicles and keep valuables out of sight.
Police wanted to hear from anyone with information about the break-ins or saw anything suspicious.
- Taranaki Daily News
Should New Plymouth council sell off assets from the Perpetual Investment Fund to pay off debt?Related story: Perpetual Investment Fund asset sell-off 'should be debated'
Get Taranaki's frequent news and sport updates
Get your mid week news fix
Get your South Taranaki news online