Anthony John Hagen, 54, is facing drug trafficking charges in the ACT Supreme Court and was released on bail in early March.

The alleged drug dealer was effectively under home detention, ordered by the court to stay at his Stuart Flats unit from 12.01pm to 11.59am.

He was also told he must give police details of his mobile phone, and not use any phone police were not aware of.

But Hagen broke both of those conditions when police found him outside his unit on Sunday morning.

Police were patrolling through Griffith when they say they saw Hagen with a second man and a woman outside the unit.

They arrested and searched Hagen, finding a mobile phone the alleged drug dealer had not told police about.

Hagen's lawyer told the court that the 54-year-old was sick from a lesion on his liver and was making his way to hospital.

Hagen said he accidentally picked up his daughter's uncle's phone, which happened to be almost identical to his own, by mistake.

But Magistrate Beth Campbell cast doubt on both of those claims when the defendant was brought before the court for a bail application on Monday morning.

She said his use of the second mobile phone led to "almost irresistible inferences" about his behaviour.

Hagen has built up extensive criminal history over the past 30 years.

He was convicted of murder in 1987, and robbed the Commonwealth Bank in Fyshwick with notorious criminal Matthew Massey in 1999.

Ms Campbell said the serious nature of Hagen's alleged offending had "again reared its ugly head", leaving her no choice but to remand him in custody.

Hagen will appear in the Supreme Court on Tuesday morning.