More than 300 inmates from Christchurch prisons are being flown by the airforce to North Island lock-ups after earthquake damage to prison buildings.
The 7.1 magnitude earthquake and aftershocks damaged prison buildings, drained sprinklers of water pressure and destroyed prisoners' sculptures and artwork.
All 135 prisoners from Christchurch Women's prison have been transferred to Auckland, while 90 prisoners from Christchurch Men's prison went to Otago yesterday.
By tonight more than 300 prisoners would have been flown to North Island prisons on the airforce's Hercules aircraft.
Corrections Minister Judith Collins said the prisoner transfers were necessary, as there were safety concerns and insurers needed to inspect severely damaged buildings.
A 5.1 magnitude aftershock this morning further destabilised prison infrastructure and contractors were working to restore water pressure for sprinklers, in case of a fire.
Double bunking in prisons meant there was space to relocate prisoners.
"We can't just close up, it's not like just shutting a business. We have to think about public safety and staff safety,'' Ms Collins said.
"The prisoner relocations will allow some staff to take time to be with their families and deal with any earthquake impacts on their homes.''
Thirty staff from Auckland and Otago prisons had helped the defence force with the transfers.
Corrections spokesman Lance Alexander said male prisoners were being shifted to Waikeria and Spring Hill prisons in the Waikato, and Rimutaka prison in Upper Hutt.
Double bunking would be used when available.
"All of these sites have capacity and staffing available,'' he said.
Other prisons would also be affected as prisoners were moved to make room.
Ms Collins met staff at Christchurch Men's prison today to inspect the damage and thanked them for their dedication.
She praised the way many put personal problems aside, left family behind and turned up for work. Now they could focus on their homes and families.
Corrections said the prisoners transfer was a temporary move and though there was no date for their return, it would be as soon as possible.
"We are grateful for the assistance we have received from Defence, for their help in flying prisoners out of Christchurch,'' Mr Alexander said.
"We have a responsibility to ensure that the public are safe by securely containing prisoners, and unfortunately Saturday's earthquake and subsequent aftershocks have compromised our ability to do this in Christchurch.''
"This morning's strong jolt has destabilised the prison infrastructure further. Yesterday the focus of contractors' was restoring water pressure to enable sprinklers to function.
"Today our focus is on reassessing buildings for their suitability to securely house prisoners and be safe workplaces for our staff.
"The last thing we would want to do is add further pressure to emergency services in Canterbury and divert them from working in other parts of the community. A risk to the safety of the public and our staff existed and we needed to move prisoners quickly and safely to mitigate this.''
