Police are working on the theory that the man was alone and has not been the victim of any crime.
“We want to, as far as possible, exclude the possibility that he has fallen ill or been the victim of an incident, and is in the vicinity of the vehicle,” said Per Wahlström at the local police to the Piteå-Tidningen newspaper.
Police have been joined in the search by the home guard, sniffer dogs and a helicopter.
The abandoned car was found on Saturday on the side of a route 747 located about 20 kilometres west of Jokkmokk in the far north of Sweden.
An initial search for the man over the weekend proved unsuccessful.
The unlocked car was rented in the Czech Republic. Inside police found bank cards, car keys, some cash and a driver’s licence of the 26-year-old man believed to be the driver.
The car was collected on Wednesday by the rental company and returned to the Czech Republic and police subsequently released a photograph of the missing man.
Anyone with information about the car, a white Ford Mustang GT convertible with Czech licence number 2AK9676 or the missing man, is encouraged to contact police at 114 14.