POLICE have uncovered about 18kg of steroids in a series of raids across Adelaide.

Officers from the Drug and Organised Crime Task Force, along with NSW Police and Australian Border Force, raided four Adelaide premises on Tuesday.

They uncovered the various steroid powders and numerous vials of steroids at a warehouse in Kilburn.

A Tranmere man, 36, has been arrested over the raids.

Police will allege that more than 1000 vials of various steroids were sent to NSW from South Australia.

The man will appear in the Adelaide Magistrates Court today where NSW Police will seek his extradition.

He is expected to be charged with supplying a commercial quantity of a prohibited drug.