Prof Tim Bentley, Massey University School of Management's healthy work group director, said the figures on serious harm or injury incidents included in the report were low because many injuries went unreported.
The review was requested by Prime Minister John Key after he received a letter from Chris Jordan, the father of Emily Jordan (21) who drowned in the Kawarau River in April 2008 while on an excursion with Mad Dog River Boarding.
The 95-page report, compiled by Labour Minister Kate Wilkinson, found industry-wide safety inconsistencies.
Prof Bentley said he had studied adventure tourism industry injuries for 10 years and many injuries to overseas visitors were "never reported to official bodies such as the Department of Labour".
His latest paper, "A decade of injury monitoring in the New Zealand adventure tourism industry", was published in the journal Tourism Management and supplied to department staff carrying out the review.
One of the recommendations from the report, for a comprehensive injury-monitoring system, was something he had been advocating "for many years".
"We need a single body to collect and collate the information, and this system should include reporting near misses, as well.
"If you want to do something about a problem, you need to understand it."
The report did reflect the "many injuries" in certain areas of adventure tourism, for example horse riding (40 in the five years from July 1, 2004) and quad biking (26 for the same period). It was where "you can't control behaviour of participants that there is a bigger problem", he said.
"With bungy, you can control behaviour minutely and control the technology and activity location, but with something like mountain biking or horse riding, there is far less control. This is where we have to better manage the organisation of activities and build a safety culture."
Prof Bentley said registration should be mandatory for all operators in the adventure tourism industry, regardless of the risk profile of the activity.
"We need to see how far-reaching the registration they are suggesting is, because it is not clear at the moment."
