The Australian Civil Aviation Safety Authority has suspended the air operator's certificates of Skymaster Air Services and Avtex Air Services.

The charter operators, which share the same ownership, have been told by CASA that the continuation of their licence could pose a serious risk to air safety.

CASA said its decision was due to the three serious accidents and other incidents involving Skymaster and Avtex aircraft in the last three months.

It said other issues relating to safety culture, aircraft maintenance and pilot training were also taken into consideration.