Clive Norling, Wales's director of refereeing, has issued a warning following the attack on Ireland's David McHugh during last Saturday's Tri-Nations match between South Africa and New Zealand in Durban.
"It is time some people realised, that without the referee, there is no game of rugby," Mr Norling said.
"Sadly, last season we had two incidents in our Welsh/Scottish League where referees were physically threatened.
"My major concern is the effect that an incident like we saw in South Africa could have on the recruitment and retention of referees.
"Hugh Banfield, the secretary of the Welsh Society of Referees, and myself have been banging the drum for the last 18 months because we feared something might happen because of of the global abuse of referees."
Nearly 40 players were involved in the first Wales Under 18 training session of the season. WRU National Performance Manager Gethin Watts is excited at the potential shown by the group and expects the Regional Under 18 Championship to hone their skills even further.