Police are asking vehicle owners to exercise vigilance after a sharp increase in car thefts in Invercargill and Southland over recent months.

Police said they believed a group of Invercargill youths were responsible for many of the vehicle thefts and also the recent burglaries targeting Vape stores in Invercargill and Winton.

While three of the group of youths are currently before the youth justice system, Police said their investigations are continuing.

Vehicles being targeted are earlier model Mazdas, Nissans and Toyotas, they said.

Owners should ensure their motor vehicles are locked and if possible, securely parked overnight.

Consideration should also be given to installing an immobiliser or an additional locking device, they said.

Anyone who has information should call 105 or crime stoppers anonymously on 0800 555 111 and reference file number 231101/8120.

If anyone witnesses any suspicious behaviour around vehicles, please call 111 immediately.