The company that imports and sells Subarus in New Zealand says police have not contacted it about a surge in thefts of the brand across coastal Otago, even as officers refuse to say which models are being targeted.

RNZ reported on Wednesday that Inchcape New Zealand, which handles Subaru's distribution, marketing and retail here, had heard nothing from police about stolen vehicles or any security weakness. Its general manager, Paul Mallard, told RNZ that Subaru New Zealand was not aware of any security vulnerabilities in vehicles sold new in this country.

The response follows a public warning from Otago Coastal Police on Monday. Inspector Sam Ramsay said officers had recorded close to 30 incidents involving stolen Subarus across the Otago Coastal area since August, with a marked rise during October. Most were taken from public streets in residential parts of Dunedin and the surrounding district.

Ramsay said many of the vehicles showed little or no sign of forced entry and that investigations pointed to offenders "exploiting vulnerabilities in some vehicles". Police have declined to say which models are affected or how the cars are being taken, arguing that spelling it out could help other offenders.

That silence leaves Subaru owners across the lower South Island guessing about whether their own vehicle is at risk.

Police said a number of the stolen cars had since been recovered, but they were concerned about them being driven on local roads in the meantime, and said they were following several leads.

The warning so far applies only to the Otago Coastal policing area around Dunedin. Southland police have not issued a comparable alert, and the RNZ report made no mention of Invercargill. Southland and Otago sit within the same Southern police district, however, and vehicles stolen in Dunedin are a short drive from Gore or Balclutha.

The advice from police is the same regardless of where a car is parked. Owners should lock their vehicles every time they leave them, including at home, park off the street or in a locked garage where they can, and consider a visible deterrent such as a steering wheel lock, an alarm or an immobiliser.

Anyone who sees a theft in progress should call 111. Information about suspicious behaviour around parked vehicles, or about any of the thefts since August, can be passed to police online or by phoning 105.