A 50-year-old man serving home detention has admitted the gunpoint robbery of a Christchurch pharmacy.

Dennis Mark Quinn was remanded in custody for sentencing on October 1 by Christchurch District Court Judge Michael Crosbie, who called for a reparation report and pre-sentence report.

Quinn, unemployed, was earlier one of the people who admitted being involved in the computer theft crime ring busted by the police's Operation Wizard investigation in June 2008.

He was on home detention in July when the robbery of a pharmacy in Innes Road, St Albans, took place. Police prosecutor Sergeant Paul Brocas said Quinn was allowed to leave his St Albans home between certain hours and that was the time when the robbery occurred.

He went to the pharmacy on July 30 and made a purchase on eftpos for $2.50 but went back a few hours later.

He parked a car about two blocks away and went to the shop wearing a sweatshirt and hood, and with a scarf over his face. He carried a satchel.

He went into the dispensary area and pulled out a black pistol which he pressed into the waist of a woman staff member and demanded drugs. Two other women staff members were also present.

He then pointed the gun at a second woman and the three walked towards the safe. He told the third woman not to move. She was in an office having lunch.

He pushed the gun into one woman's side as he told her to hurry up while she was made to open the safe.

Quinn then filled the satchel with drugs from the safe. He asked for morphine. It is not yet known exactly what quantity of drugs he got away with.

He warned staff not to follow him as he ran away to the car parked in Malvern Street. A member of the public followed him but lost him at Forfar Street.

Quinn then got his wife to drive his car a short distance from their home, and she parked it where the police later found it locked and secure. The wife then phoned to report it stolen, said Mr Brocas.

The pharmacy staff were not injured but one was traumatised by having the gun pointed at her.

Police want Quinn to forfeit the car he used, and Judge Crosbie also gave him a first-strike warning under the tougher new sentencing laws.