Corrections is paying more than $3000 a day to have prison guards stay in hotels as it struggles to cope with growing inmate numbers.
It said on 8 March there were 25 staff members, who had seconded to Northland, Rimutaka and Waikeria prisons, staying in hotels.
Official information from the department showed the average cost of the hotels was $122 a night per person, excluding GST.
Corrections' deputy chief executive Vincent Arbuckle said it has seconded those staff while new staff were being recruited and trained to cope with the swollen prison population.
Mr Arbuckle said he did not expect the secondments to continue beyond mid-year.