A new report by Odyssey House, one of the country's largest residential rehabilitation services, has found admissions for opioid drugs like heroin almost tripled over the past year.

Drug use in 2015 One in three Odyssey House clients addicted to heroin, methadone, morphine or opioid-based prescription painkillers

One in three Odyssey House clients addicted to heroin, methadone, morphine or opioid-based prescription painkillers 32 per cent sought help for amphetamine drugs

32 per cent sought help for amphetamine drugs More than 600 treated at medically supervised withdrawal and residential rehabilitation programs

Amphetamines and methamphetamines are still the biggest problem for clients, but almost one in three have sought treatment for addiction to heroin, methadone, morphine or opioid-based prescription painkillers.

Eighteen months ago, Michael left his home in Western Australia to go to the Odyssey House rehabilitation centre in Sydney.

After 16 years addicted to heroin, he had reached the point where he knew it was prison, death or rehab.

"The withdrawals were horrible, they were absolutely terrible and I never want to have to go through that again," he said.

This year, Odyssey House treated more than 600 people at its medically supervised withdrawal and residential rehabilitation programs.

Space to play or pause, M to mute, left and right arrows to seek, up and down arrows for volume. Listen Duration: 3 minutes 20 seconds 3 m 20 s Listen to Lindy Kerin's report Download 6.1 MB

Thirty-two per cent of clients sought help for amphetamine drugs like ice and speed, but CEO James Pitts said there had been a big increase in admissions for opioid drugs.

"There's been a significant increase in the number of people who nominate heroin as their primary drug of choice and that's a trend that we haven't seen for at least five years or so," Mr Pitts said.

Mr Pitts said drugs go through periods of popularity.

"I've been in this business 37 years and what I've seen is ... that you have a particular drug that is a mainstay for five to eight years, and then there's another drug [that becomes popular]," he said.

"Say in the States, when you talk about the crack epidemic, I mean, prior to that it was just heroin, heroin, heroin, then all of a sudden they come up with this newfangled way to use cocaine and of course that was the mainstay for a number of years, and then it's kind of gone back and forth."

Michael is now focussing on his mural and mosaic artwork business, and his parents have moved to Sydney to support him.

"Each day I'm making amends, not by saying sorry, but by being a good son," he said.

"My mum looks like she's 10 years younger.

"My mum doesn't worry if she doesn't hear from me for a week.

"She told me that the other day, she said 'I know you're safe and I know you're on the right track and I'm proud of you'.

"For anyone in addiction who is listening, there's help out there and one thing I know for sure is that once you get clean, you're going to think about using, and that's cool, but it's definitely better than being in the gutter thinking about being clean."