A Queensland harness racing trainer who allegedly assaulted a steward has successfully appealed to have his licence reinstated.

Justin Abbott was in February disqualified for two years by Racing Queensland after an inquiry found him guilty of assaulting stipendiary steward Paul Zimmerman the month before.

That decision was quashed and set aside by the Brisbane Supreme Court on Wednesday.

Justice David Jackson found the inquiry lacked impartiality because the chief steward, who was chairman of the panel that handed down the decision, failed to disclose conversations he had with Mr Zimmerman before and after the alleged incident.

Justice Jackson ordered the allegation against Mr Abbott be referred to a different panel of stewards for a new hearing.