The unnamed official is alleged to have bet through an account held by another person on November 9 - New Zealand Trotting Cup Day.
The all-up bet was on two horses with both having to run into a placing for a collect. One of the horses was placed sixth, meaning the bet was a losing one.
The Star has learned the official under investigation also works for the trainer of one of the horses bet on.
The other horse was stabled at the trainer’s property during Cup Week.
"One person has been charged with an offence under Rule 310 of the HRNZ Rules."
Rule 310 specifies: No person acting as a starter or starter’s assistant or judge or judge’s assistant or duly appointed substitute therefore either as a paid official or in an honorary capacity shall: (a) officiate at any race meeting at which there is competing any horse in the ownership of which he is directly or indirectly interested unless he has the prior consent of the stipendiary steward; or (b) bet or be interested in any wager or bet on any race at any race meeting where he is officiating.
"As the matter is before the adjudicators the RIB will not make any further comment," Clement said.
Harness Racing New Zealand chief executive Gary Woodham also refused to comment on the basis the matter was under investigation.
A hearing date is yet to be set.