Accelerant was used on a car found burning near the Sunshine Bay boat ramp in Queenstown, police say.
Emergency services were called to the fire on Glenorchy Rd at 5am on Saturday by a member of the public.
Detective Grant Millder, of Queenstown, said the car was burnt out and a scene examination revealed an accelerant was used.
"This is the second suspicious vehicle offence that has occurred in the Sunshine Bay and Fernhill area in recent weeks," Det Miller said.
Residents in the area should ensure vehicles were locked when unattended.
