Man's disappearance could be drug related: SA police

Police in South Australia say the disappearance of a young western suburbs man could be linked to the illicit drug trade in Adelaide.

Twenty-three-year-old Paulo Jorge Miranda was last seen on the morning of May 3.

His disappearance has been declared a major crime.

Detective Inspector Doug Barr says his family and friends have not heard from Mr Miranda in more than a week.

"Paulo's mobile phone's turned off and his car that he was driving was a silver Corolla, which was his brother's vehicle," he said.

"We located that on Thursday evening out at Port Prime north of Adelaide."

Detective Inspector Barr says there is cause for concern as some of Mr Miranda's associates are involved in the illicit drug trade.

"These factors and a number of others have given us serious concerns for his welfare," he said.