The MXD (Under 19s) category of the Monster Energy MX Nationals, Australian Motocross Championship, has been restricted to competitors beneath 19 years of age for 2014.

Previously, riders who turned 19 following 1 January (meaning they were 18 at the start of the new year) were still eligible to compete in the MXD division of the MX Nationals series for the course of the season, however that option has now been removed.

The regulation update effectively prompts riders to move up to the MX2 category sooner than in previous years, unable to complete the full MXD season if they turn 19 before the final round.

It’s also been clarified that competitors must hold a Senior licence, with no provision available for 15-year-old riders.

“WEM would like to announce some changes to the Under 19s championship,” a statement from WEM said. “Effective immediately, once a rider turns 19 years of age they can no longer compete in the class, regardless of how many rounds or points they may have scored.

“All riders in this class must have a Senior national licence. There is no provision for 15-year-old riders to obtain access to this class.”

If the new rule was in effect during 2013, MXD series runner-up Jay Wilson – who turned 19 on 19 July – wouldn’t have been eligible to compete in the final four rounds of the series. He won three of those four rounds last year.

Current champion Hamish Harwood (pictured), who turns 19 on 25 April, would have been eligible to defend the title this year under the former ruleset, but he’d now be shuffled out of the category following round two. It’s understood he’s been planning a transition to MX2 fulltime for 2014 prior to the rule update.

The announcement officially rules out earlier speculation that the category age limit would be reduced to riders under 18 in 2014.