Police are warning people in Southland to keep an eye on their vehicles

Thefts of Mazdas, Nissans and Toyotas have sharply risen in recent months, in Invercargill and Southland.

It's believed a group of Invergargil youth are responsible, and also targeting vape stores in Winton and Invercargill.

Police say three youths are before the courts and investigations continue.