Auckland's maximum security prison at Paremoremo is "putrid" and not really maximum security at all, and Mt Eden is simply "archaic", according to a visiting Australian prison officers' union leader.

In a report commissioned by the Corrections Association, which represents prison officers here, Colin Rosewarne, an executive officer of the Australian Community and Public Sector Union's prisons division, said he found lax security, shortages of guards, prisoner unruliness and poor hygiene.

Mr Rosewarne said he was welcomed at Mt Eden prison and the new remand centre there, but at Paremoremo "it was fairly obvious they didn't want us there".

"After about half an hour or 45 minutes we were asked to leave," he told Radio New Zealand.

In that time, he saw that watch-towers were unmanned, movement detectors were not working, and there were no perimeter patrols.

Corrections Association president Bevan Hanlon said all these basic security features "we just don't do".

"It's about cost saving and that's what Corrections has chosen to do."

Mr Rosewarne described Paremoremo as "putrid" - the worst he had visited in Australia, Asia, and North America.

"The prison hospital was just unbelievable."

Mr Hanlon agreed Paremoremo was "a dump".

"It's in an absolute state of disrepair."

As for Mt Eden, prisoners were "extremely unruly", Mr Rosewarne said.

As the visiting party traversed elevated walkways above the prison's exercise area, they had plastic bottles and abuse hurled at them, and prisoners openly conducted a drug deal.

"They didn't even try to hide it."

The 136-year-old prison was "archaic" and too old to successfully modify, he said.

"It'd make a great museum."

Security there was lax, he said, but surprisingly better than at the newer, more high-tech remand centre.

Northern regional manager Warren Cummins said the report contained inaccuracies and Mr Rosewarne's visits were too short to make valid judgements.

"But I wouldn't discount the possibility there are better ways of doing things."