Prison officers say they need tasers in prisons to stop attacks on them.
At a conference of the Prison Officers Association of Australasia in Wellington, Australian guards told union delegates that assaults have dropped dramatically since tasers were introduced in some states.
Unions in New Zealand have been calling for better protections for officers since the killing of Springhill Prison guard, Jason Palmer, 33, in May this year. He was the first prison officer to die on duty.
Corrections Association president Beven Hanlon was going to speak about Mr Palmer's death, but has been gagged.
He received a letter from the department on Wednesday night banning him from making any public comment.
Mr Hanlon is already facing disciplinary action over comments made after Mr Palmer's death about security concerns among officers at Spring Hill.
Western Australia Prison Officers Union vice-president Ken Brown says he is appalled by the lack of protection for New Zealand guards.
Mr Brown says no officers have been injured since Western Australia introduced tasers three years ago.