St John says nine cases where ambulance response was incorrectly given a low priority did not cause the deaths of people in four of them.
The findings came from a St John investigation after concerns were raised about ambulance responses using a new protocol set up at the height of the swine flu pandemic.
Protocol 36 was introduced into Ambulance Communications Centres, where questions specifically related to swine flu were asked to help prioritise ambulance responses.
St John medical director Tony Smith says he has reviewed all cases where an incorrect response time was given and found that a faster response would not have changed the outcome for the patients who died.
The Health and Disability Commissioner's office has received no complaints about the cases to date.
Craig Page from the National Distribution Union, which represents St John employees, says staff began complaining about the system and a lack of training from the start.
The paper-based system put in place in July was meant to work alongside the existing computerised version, but Mr Page says staff cannot be expected to deliver the same level of service with two different systems running.