Some 650 inmates have been moved out of Christchurch jails until earthquake damage to prisons can be repaired.
Department of Corrections spokesperson Lance Alexander says 58 prisoners from Christchurch Men's Prison were moved to Whanganui on Friday afternoon, while other inmates have been shifted to Otago, Spring Hill, Waikeria and Rimutaka jails.
All 127 inmates from Christchurch Women's Prison are at Auckland Region Women's Corrections Facility.
Mr Alexander says the biggest worry initially was water supply, but the large aftershock on Wednesday caused more damage.
The department says overcrowding will not be a problem because 1000 additional beds were added to prisons last year through double-bunking.
