Both state and Serco-run prisons are denying some inmates with mental health problems access to their prescription drugs, lawyers say.
Alex Steedman is a lawyer and has many clients with mental health problems, who have not been able to get their prescription anti-psychotic medicines while in prison, he said.
One case involved a homeless man in a Serco-run prison seeking a bail application, although the problem was not confined to the privately run prison and occurred in state-controlled ones as well, he said.
The prisoner was meant to be receiving an injected anti-psychotic, but Serco had not given it to him for a week and when the client went to court he was in a highly agitated state, Mr Steedman said.
There was no way the judge was going to let his client out, based on how he appeared, he said.
It was not an isolated incident and others were also presenting at court without being given the right drugs to control their behaviour.
"I am aware of personal instances with clients that I've had and also talking to other practitioners that seem to confirm that medication is a problematic issue at the moment."
Alcohol and drug counsellor Roger Brooking agreed.
Mr Brooking said one prisoner who was asked to do an alcohol and drug assessment had been on remand in Rimutaka Prison for three months.
Prior to being incarcerated the man had been on anti-depressants, but in prison had not received any medicine in that time, despite wanting to take it.
"He couldn't get to see the the doctors, the doctors are only available in prisons part time. There isn't a prison in the country where there's a doctor on duty full-time, so you can have up to 1000 prisoners, and doctors on duty only 20 hours a week."
Both Mr Steedman and Mr Brooking said frequent lockdowns also prevented nurses from giving prisoners their medication and the prisoners were not able to go to the prison health centre.
That situation only worsened when medications were meant to be supplied at night, Mr Brooking said.
"So if they're meant to take medications in the evening, they'll get it delivered at 4 o'clock because the nurses go home at 5 o'clock, so there are those kind of issues as well.
"It's very difficult to get the medication you need on a regular basis and at the appropriate intervals you need them. There isn't a doctor on duty half of the time, anyway.
He said prisoners have to fill out a chit if they want to see the prison doctor and many have literacy problems which can make this difficult for them.
Kim Workman, from Rethinking Crime and Punishment, said the current stance by Corrections staff was deplorable and the problem was endemic.
"It's just inefficiencies and in some cases a lack of concern on the part of medical staff and the contracted medical practitioners that provide the services. Some of them are very, very good, some of them couldn't care less."
Auckland University law lecturer Khylee Quince said stories about the lack of access to psychiatric nurses and doctors for medication had been shared among lawyers for years.
"It is not surprising given the other functions of penal facilities that this sometimes takes a back seat.
"It may be easier to give a sedative than it is to administer and oversee management of anti-psychotic medication.
"For example, where there are medical personnel available they will be managing a high number of inmates so it could be a resourcing issue, but I think, fundamentally, they view themselves as correctional facilities not as health facilities, and therefore they view inmates not as patients per se but as criminals - they are there for punishment."
Ms Quince said a lack of training was partly responsible, but also a lack of empathy, because that was not part of their job.
"Particularly with the contracting out of prison management services to Serco - and like companies in other countries - there is even more of a service mentality that is focussed purely upon punishment than a wider holistic focus in terms of inmate well-being."
The inmates face a very different scenario from prisoners in forensic mental health units, such as the Mason Clinic, where they can be forced to take medications under the Mental Health Act, Mr Steedman said. Prisoners in other jails cannot be forced to take prescribed medications while in a mainstream prison.
Corrections director of offender health Bronwyn Donaldson provided a statement responding to the criticism saying prisoners did receive the prescribed drugs they needed.
"If a prisoner is in need of medication and the prison is locked down then arrangements will be made for that prisoner to receive the medication they require, e.g. through the hatch in the cell door or wall," she wrote.
"Corrections is a primary health care provider and will consult and work in collaboration with DHB specialist services who have been providing assessment or treatment to ensure that a prisoner's health needs are met.
"Our staff are dedicated to providing the best care possible. Corrections' health services staff are registered nurses who provide health services and support in all prisons seven days a week. Medical officers, who are usually general practitioners in the community, and dentists are contracted to provide medical and dental care.
"Prisoners have readily available access to prison health services and are able to request assistance via a health request system, or by speaking to unit staff or directly to health staff. Outside of health services operating hours on-call nurses are available to all prison sites 24 hours a day, 7 days a week."