The New Zealand Rugby Football Union ordered compulsory safety courses for referees and coaches following revelations that the game was getting more dangerous.

The ruling body said teams would be barred if their coaches did not attend the course in the next few weeks. Referees who did not attend would not be assigned to games.

The move by the union follows revelations that laws changed in the 1980s to make the game safer had little impact on the number of serious spinal injuries.