The Transport Accident Investigation Commission wants recreational boaties to hold some sort of licensing, following an inquiry into a collision on a South Island river.
Two people were killed and two others injured when a jetboat and a large jetski collided on the Kawarau River near Queenstown in January 2009.
The commission found both vehicles were travelling at an unsafe speed and the jetboat was travelling on the wrong side of the river.
It says none of the three people in the jetboat were wearing lifejackets, which would have saved the lives of the two who were knocked on the head and drowned.
The commission says one of the drivers had been drinking, but probably not enough to impair his ability to drive his boat.
Its recommendations include that drivers of recreational boats should hold a licence or certificate to show they know how to operate them safely.
Chief accident investigator Tim Burfoot says at present, people in charge of recreational boats are not required to have an in-depth knowledge of maritime rules.
People should have to prove that they understand the rules and concepts before taking charge of a boat, he says.
Other recommendations include legislation limiting the amount of alcohol that can be consumed before driving a boat, and that people wear helmets when involved in high-speed boating activities.