The Aboriginal Legal Service of Western Australia says the state government's proposed youth bail changes will undermine the administration of justice, increase the likelihood of children being imprisoned, and do nothing to protect the community.

The Western Australian government's proposed changes, announced Thursday, would see youth charged with violent offences brought to trial within 28 days and also would impose criminal penalties on responsible adults in the event of a child breaching bail conditions.

ALS WA director of legal services Peter Collins told National Indigenous Times the changes were unnecessary and would be bad for victims of crime, accused young people, and for the community in general.

"The president of the Children's Court has already introduced reforms that are working very well to ensure cases are expedited and completed in a timely fashion," he said.

"One of the big problems with these proposed changes, a critical issue, is that these changes are capable of causing significant injustice.

"From a perspective of alleged victims and their families, cases that have to be listed for trial within in 28 days mean there's a chance not all the evidence will be assembled. Such that the prosecution will be not be in a position to prove the charge to the required standard. This may result in situations where charges are discontinued completely or a guilty plea to a lesser charge is accepted. That could cause distress to victims and their families.

"From an accused young person's point of view... They may be found guilty and sent to Banksia Hill or Unit 18 and after that has taken place evidence is uncovered that not only demonstrates the charges could not be proven beyond reasonable doubt, it could even establish that the person is innocent. Particularly in the case of forensic evidence such as DNA, it may conclusively show another person committed the crime. In the case of forensic evidence, it's almost impossible to conceive of it being available for use in trials within 28 days."

Mr Collins said the proposed changes would place increased pressure on the courts, police, prosecution agencies such as the Department of Public Prosecutions, and legal services such as ALS WA.

"We already have crippling workloads causing enormous stress... these ridiculous timelines will compound these problems," he said.

He said the changes would cause harm while serving no productive purpose.

"These changes are not going to decrease the incidence of violent offending y young people. What can reduce that is early intervention, prevention and rehabilitation programs - to support and help young people turn away from violent offending," he said.

"The police minister (Paul Papalia) indicated that the best place for some young people is in detention. That is a delusional observation with no foundation in fact, and it indicates that this is a tawdry political move to garner votes at the next election."

Mr Collins told National Indigenous Times the bail changes "do not protect the community, particularly in the medium to long term".

"All evidence shows young people locked up in Banksia Hill or Unit 18 in draconian conditions are more likely to engage in serious offending on release."

He noted that the changes would likely result in more Aboriginal children being taken into custody, as courts may be more likely to refuse bail and hold children on remand, because it's a shorter wait time, and the proposed changes also would criminalise responsible adults who sign bail papers and agree to ensure children adhere to bail conditions.

"If a responsible adult does not respond to a notification from an app within a short period they could be charged; that is a massive disincentive to taking on that role as an adult, they don't want to face a criminal charge."

WA Premier Roger Cook, in touting the changes, said: "All too often, we see young offenders who are out on bail awaiting their trial, and while they're on bail awaiting their trial, they're getting up to more mischief. We just want to cut that off at the knees."

Minister Papalia said while the policy could see young offenders given community-based sentences, there was "no reason for the courts not to sentence high-harm offenders to detention".

"Having a consequence for their crimes faster will mean that they understand the consequence, and then there's a greater chance of changing their behaviour," he said.

Mr Collins told National Indigenous Times over-incarceration of Indigenous children in Western Australia remained dire, and the state showed no interest in changing that.

"The Closing the Gap target in this regard is disappearing to vanishing point," he said.

"The (WA) government is not genuine about it and never has been."