Christoffer Tornberg (23) was reported missing on October 18, after friends and colleagues had not seen or heard from him, Detective Grant Miller, of Queenstown, said yesterday.
Mr Tornberg was described as 180cm tall, with blue eyes, and of medium build. He was last seen wearing a black leather jacket, blue jeans and dark-coloured T-shirt, at his flat in Queenstown on October 6.
"We just want to know where he is. It's an unusual disappearance. His friends say it's out of character for him not to be in contact," Det Miller said.
He said he was not an outdoors enthusiast so it was unlikely he had gone tramping. Nor had he left the country.
The Swede has a working holiday visa and had lived in Queenstown for about a year.
His next of kin in Sweden have been contacted and they also expressed concerns they have not had any contact from Mr Tornberg. Any person who knew the whereabouts of Mr Tornberg was asked to contact Queenstown police, on (03) 441-1600.
