The workplace watchdog is seeking a default judgment against John Setka over allegations he tried to force the AFL to sack its head of umpires through industrial action, potentially exposing the controversial former union boss to tens of thousands of dollars in fines.

The Fair Work Ombudsman made the application last Friday after Setka, or lawyers on his behalf, failed to appear in preliminary Federal Court hearings for a third time since the legal action first launched in February.