Arrest rates for women have jumped by nearly half in some parts of England and Wales, according to new analysis.
The number of females held in 2015/16 increased compared to the previous year in nearly two out of five forces, a study from the Prison Reform Trust (PRT) found.
But arrests of women fell in the majority of areas, leading to suggestions of a "postcode lottery".
The largest increase was seen in Lancashire, where arrests rose by 46%, while similar increases were seen in Dorset (45%) and Hertfordshire (40%), the PRT said.
By contrast, Hampshire, Leicestershire and Gwent police recorded annual falls of 28%, 29% and 31% respectively, according to figures compiled by the charity.
It released the findings alongside a report setting out the case for greater use of "problem-solving approaches" for women at the point of arrest in cases where the harm caused by an offence is low, but where the individual has multiple or complex needs.
Author of the report Dr Thomas Guiney said: "The evidence is clear that point of arrest can be the ideal opportunity for effective early intervention, giving women the support they need to tackle the issues leading to their offending.
"Our report shows that this is working well in some areas - where police and other agencies are collaborating to ensure a proportionate and fair outcome. More must be done to ensure these services are available across England and Wales."
Jenny Earle, director of the PRT's programme to reduce women's imprisonment, said: "Most of women's offending is rooted in financial hardship, abusive relationships, addiction and poor mental health.
"For too long the criminal justice system has been used as a safety net to get women's lives back on track, when what is needed is treatment and support."
Chief Constable Simon Cole, the National Police Chiefs' Council lead for local policing, said: "As a member of the Prison Reform Trust advisory group, I feel this is a helpful discussion paper which underlines the importance of problem-solving and early intervention, a goal shared by chief officers and recognised in the National Policing Vision 2025.
"Over 7,000 fewer women were arrested last year compared to 2014/15 - a fall of nearly 5% and despite population growth.
"We will continue to use learning and evidence of what works to support the most vulnerable and get better still."