An increase in the number of prisoners on remand has come about because family violence is being taken far more seriously than it once was, says former Justice Minister Judith Collins.
The current minister, Andrew Little, is looking at changes to the bail laws that he says have been a cause of the spiralling prison population.
Judith Collins said the previous National government toughened the bail laws in 2013 to prevent people repeatedly being abused.
"If anybody commits a really serious offence I'd rather that they were in prison than not, and when we look at how hard it is to actually get put in prison, it is actually extremely hard."
As at last September there were 3000 prisoners on remand, compared with 1800 in 2012.
Ahead of the election, Labour called for a bi-partisan target to reduce the total prison population by 30 percent over the next 15 years.