Keith Dutton, 45, of Wilcannia, already had convictions for violence and sexual assault before he forced the woman to give him oral sex at her northside flat in September 2011.

Dutton was arrested in NSW and extradited to the territory where he pleaded guilty to committing sexual intercourse with the woman without her consent.

A sentencing hearing on Thursday heard the woman had finished grocery shopping at the Canberra Centre when she was approached by Dutton and asked for a cigarette.

He then offered to carry her shopping to her Braddon flat as he was on his way to the same complex to visit his cousin.

Upon arrival he said he did not know where his cousin lived and convinced the victim to let him wait in her unit.

When inside he offered her drugs and left briefly to return with a second man.

Dutton refused to leave later that night and boasted of his criminal history, including telling the victim he had once been shot by police after taking his family hostage.

Dutton demanded sex after the other man fell asleep and continued to repeat the order despite the woman's refusal.

He then forced her to give him oral sex for 10 minutes before discontinuing his advances and demanding she make him a coffee.

She reported the incident to police the following day.

The Crown on Thursday read a victim impact statement that said the woman had suffered panic attacks and lived in fear since the assault.

The court heard the woman's teenage son had moved to Victoria and begun carrying a knife as a result of the incident.

But the victim was also defiant, pledging to regain control of her life and not let the incident define her.

Chief Justice Terence Higgins will sentence Dutton next month.