New laws enabling Western Australian courts to keep violent criminals in jail beyond their sentence are being introduced into state parliament.
As with dangerous sex offenders, violent offenders who are nearing their release date and deemed likely to pose an ongoing risk to the community could be issued with a continuing detention or supervision order.
Attorney General John Quigley said the laws would apply to offenders convicted of murder, manslaughter and grievous bodily harm.
It would also apply to sexual offences including those involving child exploitation material.
Mr Quigley said that was due to criminals like notorious pedophile Bradley Pen Dragon, who was most recently convicted of Commonwealth offences not covered by the state's dangerous sex offender laws.
Mr Quigley also cited a man who committed violent offences against his partner, including body-slamming her into concrete, and wrote letters to the judge saying 'lock me up forever because when I get out I'll kill someone'.
The judge sentenced him to eight-and-a-half years.
"He'll be a prime candidate from the letters he's already written to the judge," Mr Quigley told reporters on Wednesday.
"I think all the community would be very concerned that a prisoner who says he's going to come out and kill someone is released."
My Quigley said bikies showing loyalty to fellow gang members would be psychologically assessed for risk of "getting back with their mates and committing a further violent offence.
"We're not going to have this community held to ransom by violent thugs."
The order would be reviewed every 18 to 24 months.
In December, the state government passed laws enabling the attorney general to instruct the Prisoners Review Board to suspend parole consideration for mass murderers and serial killers for up to six years at a time.
Australian Associated Press