Changes to the 111 emergency callout system, which would see police pull back on dealing with family harm incidents, were given the thumbs up in a trial carried out last year.
But critics say police are putting much greater emphasis on saving officers' time than keeping victims safe.
Police have begun testing a new way of handling all calls that are rated as second in priority and below.
Under the new system, police go out to fewer calls, and refer more incidents to other agencies.
That includes family harm calls of priority two or less. Priority one are calls where there is violence, and often the offender is on the scene.
Changes to 111 system criticised
A trial of this system has now come to light, run for six months last year, that is helping to smooth the way, saying there was "the potential for this workstream to not only be an answer to demand but also to strengthen the service to victims of family harm".
Police went public early this year about pulling back on family and social harm, and on mental health callouts, from November.
But the evaluation showed it has been planned since 2022, with last year's trial partly concluding:
"Staff reported having many meaningful interactions with victims who were happy that their reports were being heard and taken seriously.
"Many victims reported to staff that having the ability to report their grievance without needing uniformed officers or a marked car outside their house (for many a regular occurrence) was a real relief."
But Deborah Mackenzie, co-founder of the Backbone Collective advocacy group, said they had been left in the dark about the plans.
"It's been incredibly difficult for us to get information from police about the rollout of the pilot, and to be able to feed in and and provide any kind of critique or suggestions," she told RNZ.
When the group did get hold of the evaluation report, they were unimpressed.
"Straightaway reading the trial, the evaluation was even worse than what we had imagined.
"So not only were victim-survivors not told they were in a pilot, but they weren't contacted directly and asked about what the phone pilot was like for them.
"It shows very clearly that the impetus behind the pilot is around relieving pressure from front-line police teams rather than responding to family violence more safely and effectively," Mackenzie said.
Hohou Te Rongo Kahukura - Outing Violence Trust spokesperson Sandra Dickson said the evaluation read like a lurch back in time.
"It feels like the way... family violence has been talked about in the last sort of six months, even a year by the police has been almost going back 20, 30, 40 years to when we thought family violence looked like the bash," said Dickson.
"As opposed to what we know family violence looks like, which is cycles of harm, cycles of coercive control, and very seldom are people ringing in the middle of an actual assault."
She said police needed to stop the new system.
"I think we don't have any evidence at all this will be safe."
The evaluation report also raised the idea of non-sworn staff handling calls, under police supervision, to further ease the burden on the front line.
Ex-police officer Rob Veale - who for years has run training on countering violence, especially strangulation - said police were "time poor" but also lacked training on crimes that were not one-offs, but depend on patterns of behaviour.
He included family violence, strangulation and stalking under that - with the law on that poised to change soon.
"As long as the officers are trained, there is a possibility they might have more time to investigate serious offences such as strangulation.
"And if they get the training sorted for the new stalking legislation, that also might be helpful."
But in his experience, police training on strangulation was running years behind the law changes - the police and justice sector response was a "job half done", Veale said.
Police have been approached for comment.