St John has refused a request for ambulance officers to be issued with stab-proof vests.
The National Distribution Union (NDU) called for better protection for ambulance officers, including stab-proof vests and an end to single-crewing, after a survey found one in four staff were physically assaulted at least once a month.
St John chief executive Jaimes Wood questioned those statistics, saying it had 850 full-time officers and 2500 volunteers, and 46 assaults were reported in the last financial year.
The NDU statistics would equate to 750 assaults each month.
Canterbury District Health Board on Monday announced security staff at Christchurch and Hillmorton hospitals would be supplied with stab-proof vests as part of their uniform.
More than 500 assaults on hospital staff had occurred in the past year, The Press reported.
Last year's St John figures were down on the 2007-08 year, when 51 assaults were reported, but was up on every other year since 2003-04.
Most of the assaults did not involve weapons, Mr Wood said.
St John regularly reviewed the need for stab-proof vests and had decided not to introduce them at this stage, he said.
Ambulance officers should not be placed in situations where the vests were necessary, and wearing them may make officers feel they had to enter risky situations, he said.
However, St John supported the inclusion of front-line health workers in legislation that made attacks on police and prison staff an aggravating factor at sentencing for assaults.
Board chairman Alister James had asked the Government to include front-line health workers in the new sentencing legislation.
Health Minister Tony Ryall said he would pass the idea to Cabinet.
St John southern region operations manager Doug Third said one southern ambulance officer was threatened last year, but none was assaulted.
Usually, about one assault on an ambulance officer occurred in the region each year, but no officers had been injured as a result of assaults in recent years, he said.
The southern public were generally fairly respectful of ambulance officers, he said.
