Police in England and Wales are failing to protect victims of domestic and sexual violence, campaigners have said.
In only the second super-complaint made to a national watchdog, the Centre for Women's Justice (CWJ) says forces are not using existing powers to deal with crimes including stalking and rape.
There is a "systematic failure" to "safeguard a highly vulnerable section of the population", it adds.
The Home Office said measures were in place to help police tackle abuse.
The CWJ has lodged its super-complaint with the policing watchdog in England and Wales - HM Inspectorate of Constabulary and Fire and Rescue Services - calling for an investigation into the way criminal suspects in rape and domestic cases are being dealt with.
The complaint makes four key claims that focus on bail for rape suspects, and alleged failures linked to domestic violence, non-molestation and restraint orders.
It says they have "become concerned that the various legal measures intended to provide protection to women are not being applied properly on the ground".
The CWJ, which gathered information from 11 frontline services, highlights how changes to the bail system have led to thousands of violent crime suspects being released under investigation without conditions being imposed.
For example, it claims that most rape suspects are now released without bail conditions, meaning they are left unsupervised.
One sexual violence survivors service said that of 120 active cases, only five suspects were on bail.
The CWJ says that as a result of the changes, alleged rapists and perpetrators of domestic abuse are harassing, and in some cases violently assaulting, complainants.
Bail conditions usually include things such as agreeing not to contact certain people and reporting to a police station at set times.
The Home Office said pre-charge bail decisions were down to police forces.
It said police can use bail where it was considered necessary and proportionate, adding that it can only be considered by police on a case-by-case basis.
The changes to the bail system in England and Wales were brought in by the government in April 2017, following criticism that suspects were spending months or even years on bail without charge.
Under the new system, bail should only be used when deemed "necessary and proportionate" and in most cases it must be limited to 28 days.
However, many suspects are instead released "under investigation" with no conditions imposed.
Nogah Ofer, the solicitor from CWJ who prepared the super-complaint, said the system was currently "failing women".
She told BBC Radio 4's Today programme that women were left feeling "extremely anxious" as bail conditions were meant to "keep the parties apart and stop women being intimidated while the police investigation is going on".
The complaint from the CWJ also alleges that police treat breaches of non-molestation orders - civil orders made by the family court - as a "trivial matter", even though breaking them attracts a maximum five-year jail term.
It claims that domestic violence protection notices and orders - which are another way of restricting contact with a victim, that can be pursued without their evidence or support - are rarely used.
And it claims that police and prosecutors often overlook the chance to apply for a restraint order at the end of criminal proceedings.
A Home Office spokesman said prosecutions and convictions of domestic abuse were "up by 20% and 28% respectively since 2010".
In a statement, he said: "Our landmark draft Domestic Abuse Bill and consultation response published in January includes measures to help the police tackle domestic abuse, including the creation of a Domestic Abuse Protection Notice and Order and training for police.
"We will also continue to work with partners across the criminal justice system, including the National Police Chief's Council to ensure bail conditions are being imposed where appropriate - including to protect victims."
The super-complaint system allows organisations to raise concerns on behalf of members of the public about systemic issues.
It is only the second time the legal tool has been made to a national watchdog since it was introduced in November.