A toxicology test on the pilot of the Carterton hot air balloon that crashed killing 11 people including Bay of Plenty teen Alexis Still has revealed traces of cannabis in his system.

The interim report on the crash, released today, includes a toxicology report undertaken four days after the crash, showing traces of cannabis constituent THC, in the blood of pilot Lance Hopping.

Chrisjan Jordaan, 21, and Alexis Still, 19.

The 53-year-old was the pilot on the hot air balloon carrying ten other people that struck powerlines and caught fire near Carterton on January 7 killing everyone on board.

Transport Accident Investigation Commission (TAIC) investigator Ian McClelland says no findings had been made linking cannabis use to the accident, although he says the test results are concerning.

Ian confirmed from May 1 commercial hot air ballooning operations had been required to meet new certification requirements with the introduction of a new civil aviation rule covering adventure aviation activities.

The interim report includes detailed analysis of the balloon, events leading up to the crash and detailed flight path of the balloon.

A full investigation into the crash is still underway and a full report and analysis on the cause of the crash is expected next March.

Alexis, 19, and her 21-year-old boyfriend died along with nine other people when the hot air balloon caught fire and crashed to the ground.

Alexis was born and raised in Rotorua before moving to Wellington.