But the mitigating factors taken into account in handing down the sentence included that "the defendant regretted his actions and promised not to repeat it again. The defendant was proven not as a dealer," the judge said.

"During trial, the defendant admitted he got the drugs when he was in Bangkok for his personal consumption. The amphetamine was used by the defendant to be able to sleep due to suffering heavy depression."

Both Roberts' lawyer Edward Pangkahila and prosecutor Suhadi said they would consider the sentence. They have seven days to appeal.

Outside the court, Roberts said that he was still clean and was not happy but, rather, depressed at the sentence.

"I'm thankful to the government for the chance to recover from my illness," he added, describing it as a "hell of a problem".

Officials at Denpasar airport allegedly found 20.54 grams of the drug ice and 14 ecstasy tablets in Roberts' luggage on December 4 last year.

At one stage it had appeared that Roberts could be charged with the far more serious offence of importing drugs. Under article 113 of Indonesia's strict drug laws the maximum punishment for importing more than five grams of illegal narcotics into the country is the death penalty.

But prosecutors chose to pursue a conviction on the lesser charge of illegal use of a category 1 narcotic for personal consumption.

Assessments by Indonesian and Australian doctors had confirmed that Roberts was an addict and that he had been a user of multiple narcotics including ice, methamphetamine, cocaine, ecstasy and marijuana since the year 2000.