A serial rapist who terrorised women in Perth's western suburbs in the 1980s and has spent two decades behind bars should be released, his lawyer has told the Supreme Court.
Dennis John Lyddieth, 62, who was last year declared a dangerous sex offender, raped nine women and tied up and threatened some of them with knives between 1987 and 1991.
Lyddieth is due to reappear in court after Supreme Court Justice Eric Heenan reserved his decision at an annual review of Lyddieth's continuing detention order last month.
At that hearing, Lyddieth's lawyer Mara Barone argued that he should be released on a community supervision order for between three and five years with a curfew and GPS tracking.
The court was told Lyddieth committed most of his offences at night and his offending had involved "casing out" his victims before he attacked them.
Ms Barone said Lyddieth was "most unlikely to transform into a spontaneous rapist" if he was released and any community supervision order could be "crafted" to guard against any risk.
She told the court Lyddieth would continue with counselling and be subject to reporting and regular visits to the sex offender management squad.
Community corrections officer Julie Dabala told the court GPS devices sent an alert if someone was where they should not be or if they tried to tamper with the GPS.
Ms Dabala said the GPS devices were monitored constantly.
She said staff can communicate directly with the offender through the device and that it was possible to monitor patterns of behaviour, such as if an offender repeatedly went to a particular location.
The court was told a psychiatrist believed that Lyddieth could be supervised in the community and would be responsive to supervision.
Tony Elliott, on behalf of the State, said if Lyddieth was released, there would have to be a curfew.