A defence lawyer says police's private American-provided evidence storing system is derailing criminal trials and letting in the wrong people.
Police store video footage from tasers, and family harm interviews, with the US corporation Axon on computer servers in Australia.
An RNZ Official Information Act request has revealed it was looking at expanding that to store many more video interviews and crime scene footage with Axon.
Police said it had not audited how it used Axon.
Wellington barrister Cathie Sheat said it needed to think again about expanding, because the system was bad for justice.
"[Earlier this week] my client's judge-alone trial was postponed because I was unable to access crucial evidence that was stored on the Axon evidence system," Sheat said.
Access is timelocked to a few weeks at a time.
Defence lawyers get no warning when it is about to run out.
On the eve of the trial, Sheat was unable to look at the complainant's main video interview.
"It's certainly not in the interests of defence lawyers or defendants to have to jump through these hoops to have access to evidence," she said.
Police evidential interviews in family harm cases have all been put in Axon for the past two years; Auckland lawyers were briefed on this - Sheat said Wellington lawyers were not, as far as she was aware.
Some lawyers have protested at having to sign up to terms and conditions of a private US company to get access.
Sheat said she asked three times in the past week for access to be renewed but was only told on Tuesday it had been - after the trial.
She then could not locate the access link, so now feared some other lawyer had been given access to her case.
Once before, she had gotten access to another lot of evidence by mistake, she said.
"It's full of potential for abuse."
The trial was adjourned for two months, with the accused on bail.
"It would be irresponsible of me to do a trial without having viewed that evidence recently," Sheat said.
"It will probably be recorded in the system as a defence-caused adjournment."
Other lawyers had expressed frustration, she said.
"This happens all the time, that the access runs out."
Even once inside evidence.com, lawyers could not download or record any evidence, which they could do previously when they got it on DVD or a USB.
"It's clunky, and it doesn't work well," Sheat said.
"It's not an improvement for anybody but the police."
Expanding the use of Axon would just spread the flaws, she said.
"Don't get me started about the potential for harm in storing victim's sensitive information online with such wide and badly controlled access."
Police said they were continuing to look at options to replace their old interview recording technology, "which is nearing the end of its life".
Court staff also use the evidence.com system.
RNZ has asked the Justice Ministry if it is aware of cases being delayed by lack of access to Axon; if it has received any complaints from lawyers; and if it is aware of evidence access being given to the wrong person.
A police privacy impact assessment in 2017 on storing family harm videos on Axon said there was "as yet" no planned audit into this.
Asked about that this week, five years on, police told RNZ: "An audit has not been conducted or is currently planned."
The 2017 report recommended regular targeted auditing of the database and that police seek annually updates on its security.
Police said the firm frequently organised independent penetration testing, the latest this year.
"No notable vulnerabilities were discovered as part of the most recent test."
They would review the latest tests when it was time to re-accredit the system.