The workplace watchdog has launched legal action against former CFMEU boss John Setka for allegedly trying to coerce the Australian Football League into sacking the head of umpires by threatening to disrupt its building projects.

The Fair Work Ombudsman alleges the Victorian branch secretary engaged in unlawful coercion and adverse action because the head of officiating Stephen McBurney exercised his workplace rights by initiating more than 50 court actions against the CFMEU as head of the Australian Building and Construction Commission between 2018 and 2023.