Amphetamine abuse has been found increasing in Australia with users getting younger each day. This was according to the latest annual report released Monday by Odyssey House, a rehabilitation center.

For the second year now, amphetamine addiction rate is higher compared to alcohol, cannabis and heroin. While users start experimenting with the drug at age 16 or 17 a decade ago, now users are found starting in their early teens.

A paramedic watches a drug user as he prepares himself for an injection with a narcotic drug inside a supervised injection hall in Athens November 25, 2013. Greece has set up its first "drug consumption" room to contain a surge of infectious diseases among drug addicts in the crisis-hit country, Greece's Organisation Against Drugs, OKANA, said on Monday. REUTERS/Yorgos Karahalis

Compared to the 2003 data, amphetamine addiction has grown 120 percent, mainly because heroin supply had dried up in Australia.

Amphetamine is a synthetic, addictive and mood-altering drug used illegally as a stimulant and legally as a prescription drug to treat children with ADD and adults with narcolepsy.

Ten years ago heroin was Australia's worst battleground. While the country managed to curb it, it didn't foresee a relative upswing in the use of amphetamines and the growing number of users.

"Because of the reduction in heroin availability, that amphetamines have replaced that," Jamie Pitts, chief executive of Odyssey House, told ABC's AM. "Amphetamines are cheap right now."

"It is now the drug nominated by one-third of the people who are entering our treatment program."

He noted people turned to ice and speed because it's more readily available and affordable.

The study also saw that substance abuse in Australia starts early among the teens.

"When I first got into the business, 35 years ago, most of the time when you looked at the onset of someone's drug use it was at that time - you know, 18, 19 years old before people really got stuck into on a habitual basis," Pitts said.

"Now that age has dropped down to 12 and 13, at even in 2003 it was 16 to 17 years of age," he stressed.