A German police union has called for the "complete decriminalisation" of cannabis use in the country, saying current policy is neither "intelligent nor productive" for society.

The head of the German Detectives' Federation, Andre Schulz, told the daily Bild that there has never been a human civilisation without drug consumption and that it was time the law reflected that reality.

"Prohibition created the biggest problems in the first place," he said, including fuelling more serious types of crime and stigmatising casual users.

"It is often we police officers who have to deal with those side effects such as drug-related crime, production of drugs, trade and smuggling and narcotics deaths."

Mr Schulz called instead for education encouraging "responsible" drug consumption, better treatment for addicts and programmes to protect children and youths.

He added that cannabis use should remain illegal for drivers on safety grounds.

Under German law, possession of small amounts of the drug for personal use is generally not criminally prosecuted.

The policy varies based on region but the upper limit is usually 10-15g.