In an extraordinary escalation, coalition senators confirmed they would summon Mr Joyce when he next returns to Australia and wouldn't rule out further legal action if he doesn't comply.
It capped a tense morning of questioning, with senior transport bureaucrats stonewalling attempts to release internal documents about the government's decision to block Qatar Airways' bid to double its flights to Australia.
The coalition declared only Prime Minister Anthony Albanese, Transport Minister Catherine King and Mr Joyce could explain why the decision was made.
Asked twice if they would seriously consider trying to jail Mr Joyce if he didn't comply with the summons, Senator Bridget McKenzie would not rule it out.
"There are a whole raft of processes within the standing orders and the procedures of the Senate which will eventually make it very hard for former CEO Joyce to not appear," she told reporters.
"He sought to rip his customers off, pocket over half a billion dollars worth of COVID flight credits, sold tickets to ghost flights and who indeed illegally sacked 1700 workers ... this was no ordinary CEO."
The Senate could theoretically jail someone found to be in contempt for up to six months.
Mr Joyce had told the Senate committee he couldn't attend their inquiry in person or via video link due to personal obligations while overseas, and could only be formally summoned once back in Australia.
The inquiry is due to report by October 9 but the parliamentary committee has indicated it intends to summon Mr Joyce regardless of whether he returns before that date.
Senator McKenzie also formally invited Ms King to front the probe, after her office was caught instructing a senior Transport Department official to not answer one of the inquiry's questions about a meeting with Mr Joyce.
"MO (minister's office) view is it is not for the department to answer re the minister's diary the question should be directed to the minister," the text sent from her office to deputy secretary Marisa Purvis-Smith read.
That prompted a stinging rebuke from frustrated Coalition Senator Simon Birmingham.
"If Minister King's office is saying 'get stuffed' when her own department is seeking to provide information to this committee, then Minister King should front up herself," he told the inquiry.
"It is completely unacceptable."
The inquiry uncovered that Qatar had officially asked the Albanese government to rethink its decision to block the extra flights.
It was told Australia received the formal request in August and had 60 days to respond.
Australian Qatar Business Council chair Simon Harrison said the decision to block the additional flights was frustrating, adding there was a "high probability" there was a sweetheart deal between Qantas and the government.
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