The authors of a report criticising aviation regulators following a skydiving plane crash which killed nine people in 2010 say there are lessons to be learned by all adventure tourism operators.

The modified topdressing plane, carrying four foreign tourists, four tandem jumpers and a pilot, had too much weight in the rear of the plane when it tried to take off on September 4, 2010, causing it to rise very sharply and at too low a speed to be controllable.

Transport Accident Investigation Commission (TAIC) investigator Ian McClelland says the plane flew regularly with eight passengers, producing too much weight in the rear of the plane, and the owners and pilot were not checking weight and balance as they should be.

But he also says regulation of adventure aviation was not what it should be, that the modifications to the plane were poorly managed, and discrepancies in the modification documents weren't picked up by the Civil Aviation Authority (CAA) when it approved them.

"The CAA lost the opportunity to correct the company's errors," Mr McClelland said.

Englishman Chris Coker, whose son Bradley Coker died in the crash, called on Prime Minister John Key to review the industry, saying that until regulation was radically tightened, he would advise people to think twice before visiting New Zealand for adventure sport.

TAIC chief investigator of accidents Captain Tim Burfoot says regulation has improved but noted the findings about the need for greater regulation had wider implications.

"There are some lessons to be learned from this across all areas of adventure tourism, including the need for proper regulatory oversight."

CAA director Graeme Harris agreed the CAA hadn't regulated the parachuting sector closely enough at the time.

"In the intervening year and a half the regulatory landscape controlling these operations has been transformed."