The Government claims it has saved $30 million, as it continues with plans to extend the amount of double bunking in the country's jails.
Corrections Minister Judith Collins says more than 700 bunks have been installed in Northland, Spring Hill and Otago prisons.
The installation of the final 170 bunks at Auckland Region Women's Prison is also underway.
Mrs Collins says double bunking has saved $30 million on the original budget of $107 million.
She says when the project is completed in September, it will add nearly 900 prison beds to the prison population.
