A young drug dealer was told by a judge if he had been convicted of the same offence in Singapore he would have been hanged "no questions asked".

Corbyn Williamson (20) appeared for sentencing at the Invercargill District Court on Thursday. He faced charges of possession of ecstasy, possession of cannabis, possession of LSD and possession of cannabis for supply in Invercargill on May 13.

The summary of facts said police were undertaking an operation targeting the safety of modified vehicles on that day when Williamson did a U-turn in his modified car in front of them.

While the car was being inspected, police noticed a smell of cannabis.

They then invoked a warrantless search for drugs and Williamson admitted there was cannabis for personal use in a protein powder container.

A total of 569.39g of cannabis, 15 LSD tablets, 7.78g of MDMA and $6645 was found by police during the search.

Defence counsel Scott Williamson told Judge Ajit Swaran Singh that his client's drug use had started after he suffered concussions and was diagnosed with depression and other mental health issues.

His use of drugs then led him to becoming a seller.

"It's obviously a pattern this court see far too often."

Williamson said he hoped his client being caught would stop his criminal career before it started.

Judge Swaran Singh told the defendant if he was in Malaysia or Singapore he would be hanged for these convictions.

However, he took a more rehabilitative rather than punitive approach when sentencing yesterday.

Williamson was sentenced to 18 months' intensive supervision and four months' community detention. The judge also ordered forfeiture of the cash and destruction of all drug paraphernalia.