Justin Bieber's toxicology report requested as part of a recent arrest in Miami has come back positive for marijuana and prescription drugs.

The singer was arrested and bailed by police recently in Florida on suspicion on DUI, driving without a valid licence and resisting arrest.

He claimed at the time that he had been smoking marijuana "all day" and had taken prescription drugs, as well as some beer.

The toxicology results have come back and he has tested positive for marijuana, THC and Alprazolam, which is key ingredient in anti-anxiety drug Xanax.

Bieber tested negative for other drugs such as cocaine and opiates.

Defence attorney Michael Grieco commented: "There's indications that he had Xanax in his system, which is an anti-anxiety, and then you also have marijuana in the system, which he didn't have a prescription for, but that combination even with a small amount of alcohol is a cocktail that definitely can lead to impairment."

The case is due to hit court again on February 14.