Chief Justice Dame Sian Elias has floated the prospect of prisoners being ordered free by the Government to help solve the problem of overcrowding behind bars.

In a speech she admitted would be controversial, Dame Sian said that the booming prison population had to be managed to prevent overcrowding causing "significant safety and human rights issues".

"Other countries use executive amnesties to send prisoners into the community early to prevent overcrowding.

"Such solutions will not please many ... But the alternatives and the cost of overcrowding need to be weighed."

Dame Sian used the speech, made public last night, to signal several changes were needed to be considered in criminal justice.

They included reducing the prison population as well as intervention, community education, probation and improvements in mental health care.

She said optimism had given way to pessimism and there had been a "rise of popular anxiety about crime".

There needed to be "better communication about why alternatives to prison are in the public interest ... to counter community scepticism".

Prison population figures have risen to 8400 and are expected to rise further.

Dame Sian said the question had to be asked as to whether making community-based sentences work needed "more resources and community support".

And the probation service was "overwhelmed by its case load, under-resourced to do the job and insufficiently supported ... by the public."

She concluded changing the system would require public acceptance that risk could not be eliminated and that "the costs we are absorbing to try to do so are disproportionately expensive".

"If we are not prepared to relax the pressures to contain risk in the discretionary decisions as to bail and parole, then the only other option may be to confront the length of sentences directly."

That could be achieved by "statutory changes to bring down the parole component of the sentence ... and early release amnesty. Are we ready for solutions such as these?"