Victoria’s prison watchdog has made an extraordinary intervention into Premier Jacinta Allan’s crime crackdown, warning it leads to less humane treatment of young inmates, less effective rehabilitation, and no improvement in community safety.

In a highly unusual move, Victorian Ombudsman Marlo Baragwanath wrote to state MPs about a policy debate, outlining a 20 per cent surge in complaints from prisons and youth justice services compared to the previous year.

“Conduct issues being raised with our office include use of force, misuse of power, and serious professional misconduct,” she wrote to senior MPs in a letter seen by the ABC.

She said serious professional misconduct now accounted for 14 per cent of all complaints about Corrections and Youth Justice, up from 8 per cent the year before.

On current projections, she said, the office was predicting a 157 per cent increase in youth justice complaints even before the Adult Time for Violent Crime changes become law.

“Our work shows that rapid increases in the number of people in custody lead to less humane treatment and less effective rehabilitation, which does not improve community safety in the long run,” she wrote.

A woman with chin length blonde hair, dark rimmed glasses and a cream suit and cream top sits near a pot plant reading a report.

Marlo Baragwanath predicts there will be a 157 per cent increase in complaints about the treatment of children in youth detention. (Supplied: Victoria Ombudsman)

The ombudsman does not inquire into or investigate pure government policy, but Ms Baragwanath said she had a role to identify, expose, and prevent maladministration and human rights breaches that flow from such policy.

Ms Allan’s new approach echoed the Queensland Liberal National Party’s successful campaign from opposition for “Adult Crime, Adult Time”, which helped it win last year’s state election.

But, Premier David Crisafulli’s government was also investing in greater crime prevention and rehabilitation programs as part of its crackdown on crime.

It had also set up more robust oversight of youth justice, something Ms Baragwanath urged Victoria to follow.

“Nowhere else does the state have such control over an individual as when they are incarcerated,” she wrote.

“Victorians and parliament need to be assured that wherever there is such extraordinary power, there is also independent oversight and prevention to ensure humane treatment and effective rehabilitation.”

A tall barbed wire fence can be glimpsed between silhouetted trees in front of an orange sky.

The ombudsman says there has been a 20 per cent increase in complaints about alleged use of force, misuse of power and misconduct in youth detention in Victoria over the past year. (ABC News: Jake Sturmer)

Greens leader Ellen Sandell said it was an “extraordinary” intervention from the ombudsman.

“It is quite unprecedented to get a letter like this from an independent officer like the ombudsman, and it shows just how worried she is, and how worried the community should be about Labor’s new laws because they won’t increase community safety, and, in fact, will lead to serious risks in our prison system,” Ms Sandell said.

“Premier Jacinta Allan has introduced these laws for a headline to cling to power desperately, rather than actually looking at the policy of what works and the oversight that is required.”

Opposition leader Brad Battin was also sent the letter. He said he is committed to more oversight of prisons as well as prevention and rehabilitation.

“If your justice system is failing the kids that are going in and they’re coming out worse, then it is the government’s fault and responsibility to fix that,” Mr Battin said.

The opposition has pledged more than $100 million to prevention and rehabilitation programs should it win next year’s state election.

The government hoped its new tough on crime approach would ease the political pressure it was under over law and order.

The Adult Time for Violent Crime policy has been widely criticised by experts who say it will do little to promote community safety and will lead to recidivist young offenders.

The Victorian government has been contacted for comment.