Prison guards are to receive body armour, batons, pepper spray and communication classes to help them deal with the "most difficult and dangerous people", Corrections Minister Judith Collins says.
They will receive increased tactical communications training and more personal protective equipment, to help keep themselves safe.
Major assaults were rare but "low-level assaults" happen "almost every day" in prisons, Ms Collins said.
"The safety of staff and the public is my No 1 priority."
Up to 3500 staff will receive an extra three days of training.
New personal protective equipment will include stab resistant body armour, spit hoods, batons and pepper spray available for specific situations.
The changes follow a study of assaults on staff, which suggested steps that could be taken to make staff safer.
Corrections Department assistant general manager Brendan Anstiss said verbal communication skills were the "greatest tool in any confrontation or incident".
He said the new equipment was introduced after "careful consideration" and staff would not carry the items at all times.
The introduction of Tasers was considered but it was not recommended that they were introduced at this time.