The Centre Against Sexual Assault expects the app will help lower barriers for assaulted women who do not want to report incidents.

The head of the south-east branch of CASA, Carolyn Worth, said the agency was developing the app – the first of its kind in Australia – to record patterns of crime against women.

The idea of the app came after the death of 29-year-old Irish national Jillian Meagher in September.

The new app will allow users to use their mobile phone to anonymously post details about threatening sexual behaviour, including the time and place it occurred and a description of alleged offenders. The data collected will then be given to police.

Users can also seek counselling services through the app, which is expected to be released early next year.

Ms Worth said the Crime Stoppers-style app was aimed at women who would not usually report an assault. “Many women who are sexually assaulted, often in a very serious way, don’t report it,” Ms Worth said. “We know this because they come to us for emergency contraception and sexual health tests. Many say they would be happy to do something without going to the police. This is something they can do.”

Victoria Police recorded more than 8300 cases of rape and sexual assault in the 2011-12 financial year. But according to the Australian Centre for the Study of Sexual Assault, only one in six women attacked report it to authorities.

Moorabbin Sexual Offences and Child Abuse Investigation Team’s Detective Sergeant Matt Campbell welcomed apps that used GPS to track offenders.

“Any app that provides coordinates would certainly assist us,” he said. “But I would firstly encourage anyone who is assaulted to ring triple-zero. If a victim comes forward and makes a statement we can start investigating immediately.”

But Ms Worth said a third of women who attended CASA clinics within a couple of days of a sexual assault did not want to go to the police. “This is the time they are most likely to report,” she said.

Ms Worth said the app would not provide the same detail as American versions, which show sex offenders with headshots on a map. She labelled those apps a “bad idea”.

Ms Worth acknowledged the risk of false reporting but said the app would identify patterns of behaviour rather than isolated incidents. “We’ll only refer incidents that have similar times, locations and descriptions,” she said. “Police still need evidence.” – Beau Donelly