Shabana Mahmood, the justice secretary, has declared that “prison isn’t working” for women as she announced a package of measures to reduce the number of females in the prison estate.

Plans to treat more women in the community, resolve cases involving women before they get to court and drive down the number of young women self-harming will be drawn up by a new body of experts, the justice secretary said in a conference speech on Tuesday.

Alluding to the phrase popularised by the former Tory home secretary Michael Howard, who said in 1993 that “prison works”, Mahmood said the system had failed female offenders and pledged to cut the number of women’s jails.

She added: “For women, prison isn’t working. Rather than encouraging rehabilitation, prison forces women into a life of crime. After leaving a short custodial sentence, a woman is significantly more likely to commit a further crime than one given a non-custodial sentence.

“The shameful fact is we have known this for two decades. In 2007, Baroness Jean Corston – another pioneering Labour woman – undertook a landmark review. It was clear then, and it is clear now, that if we change how we treat women in prison we cut crime, keep families together, and end the harm that passes from one generation to the next.

“For that reason, I am today announcing that this government will launch a new body – the Women’s Justice Board. Its goal will be clear: to reduce the number of women going to prison, with the ultimate ambition of having fewer women’s prisons.”

She pointed to evidence that about two-thirds of women are imprisoned for non-violent offences and that most (55%) are victims of domestic abuse. She described women’s prisons as “desperate places” that are “hurting mothers and breaking homes” and “forcing women into a life of crime” rather than rehabilitating them.

The board will publish a new three-pronged strategy in the spring, she said. “Firstly, how we intervene earlier, looking at how to resolve cases before they go to court. Secondly, how we make community support – such as residential women’s centres – a viable alternative to prison. And, thirdly, how we address the acute challenge of young women in custody, who are less than a 10th of the population, but who account for over a third of all self-harm,” she said.

Earlier on Tuesday, the prisons minister, James Timpson, told delegates at a fringe meeting that he sees “lots of very ill women” when he visits prisons and will drive down the numbers incarcerated.

“We need to decide as a society what is the best way to help these women. And when I was younger, my parents were foster parents and my mum specialised in looking after the babies of women who were inside the prison. So we spent hours and hours waiting outside of the prison while my mum went in.

“And even then, it felt wrong, and it feels wrong now,” he said.

Community orders should be “trusted more by the courts” as an alternative to jail, Lord Timpson suggested, signalling a potential change in approach to dealing with lower-level crimes.

The government has ordered a sentencing review, which is expected to begin this autumn and come forward with proposals in the spring.

Mahmood was forced to announce an early release scheme for prisoners just days after taking office following warnings that the prison system was at breaking point.