Controversial "double-bunking" is likely to be introduced to Hawke's Bay Prison following an unexpected blow-out in the prison population, Corrections chief Ray Smith says.

The Corrections Department faced questions in a select committee yesterday about its plans to cope with a record-high prison muster, where it was revealed up to 130 more prison cells nationally could be double-bunked.

Mr Smith said double-bunking was not new in New Zealand. About 30 per cent of the prison population were double-bunked, compared with 70 to 80 per cent in South Australia.

He said two prisoners to a cell had not led to an increase in violence, as some critics had claimed.


"It's not ideal in some situations, but if you do it well, it's fine," Mr Smith said.

Speaking out against the initiative was Corrections Association of New Zealand president Alan Whitley, who said the prison-specific union was not keen on double-bunking.

"We call it overcrowding - the whole design of the place is around a set number of prisoners. When you're cramming people in a place they get a little bit tetchy with each other.

He said the introduction of the double-bunking also impacted staffing levels, both in the units and ancillary staff, but the Department of Corrections had said they would follow correct processes.

The initiative would probably be introduced at Hawke's Bay Prison, which had the most capacity.

Sensible Sentencing Trust founder Garth McVicar said he didn't have a problem with the proposal.

"It's not new to New Zealand and I've seen it in prison systems in Arizona, California and London where it works well with the low-level offenders. It keeps costs down for the taxpayer and is nothing like the hotel-type prisons we have here presently."

Corrections was also delaying closing prisons, including Waikeria in the Waikato to cope with growing prisoner numbers.

Mr Smith stood by the decision to close jails while the prison population was growing, saying some older institutions were "inhumane" and "dangerous".

Another 270 prison beds would be available in April following renovations at various jails. The prison muster rose to 9360 last month, contrary to long-term forecasts of a fall in prisoners, and is expected to rise further.