Chief Justice Terrence Higgins.

Chief Justice Terrence Higgins. Photo: Karleen Minney

A hepatitis C-positive drug addict who robbed a northside chemist with a blood-filled syringe will spend one year behind bars.

Aaron Khan was on Monday convicted of aggravated robbery in the ACT Supreme Court after pleading guilty to holding up the Capital Chemist in O'Connor earlier this year.

Khan admitted at a sentencing hearing last week that he used a syringe as a weapon because he knew it would scare the pharmacy employee into handing over drugs.

On September 2, the 28-year-old entered the Sargood Street store about 10.30pm and threatened staff with a blood-filled syringe, demanding morphine sulfate.

Staff members handed over five packets of the narcotic and he left the shop.

The court heard he knew he was infected with the blood-borne disease hepatitis C at the time.

Khan said he carried out the robbery because he was being stood over for $190.

The defence tendered records of text messages sent to the defendant in the days leading up to the robbery. One text said: ''Don't make me call the boys.''

Khan said he thought he would be kidnapped and harmed if he did not obey.

''I was reluctant to do it … [but] I was scared,'' Khan said.

''I wasn't thinking about the consequences.''

The court heard Khan demanded prescription medication because it had ''high appeal on the street''.

Khan denied the drugs were for personal use: ''If it were for me I would've taken amphetamine or methamphetamine,'' he said.

Chief Justice Terence Higgins said Khan's early guilty plea and minor criminal history entitled him to leniency.

''[But] the offence is a serious one and one which attracts a period of imprisonment.''

Chief Justice Higgins noted Khan had an ''unfortunate background'', including a childhood marred by domestic violence, a history of drug and alcohol abuse since age 13 and mental illness.

The judge accepted that the defendant felt genuine remorse and showed good prospects of rehabilitation.

He jailed Khan for three years, backdated to take into account 96 days already spent in custody, with a non-parole period of 12 months.

He recommended Khan spend his time behind bars in the Solaris program for the treatment of substance misuse.