Structural engineers are to inspect the three prisons in Canterbury for signs of damage after Saturday's quake.
Inmates at Christchurch Men's Prison were locked down for most of the day, but limited visits were allowed at Christchurch women's and Rolleston prisons.
The prisons ran on back-up generators until power and water supplies were restored.
The Corrections Department says limited damage has been found so far, apart from some to a facade in a very old part of a building at Christchurch men's Prison.
