The lack of reporting by police on its own Armed Response Teams has been blamed for undermining any permanent roll-out.
Police documents show the teams reported on just 17 percent of the events they went to in the trial's first two months.
Professor of Biostatistics at Auckland University, Thomas Lumley , told RNZ reporter Jordan Bond if officers were able to pick and choose which events to record, that poses a serious problem to the integrity of the data.
