Former Qantas boss Alan Joyce has been threatened with jail time if he refuses to front a public inquiry into the blocking of extra flights from Qatar.

In an extraordinary escalation, Coalition senators confirmed on Thursday they would summon Joyce when he 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 the decision.

Asked twice if they would seriously consider trying to jail 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 said.

“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.

Earlier this week, Joyce told the Senate committee he couldn’t attend its inquiry in person or via video link due to personal obligations while overseas. He can be formally summoned only once back in Australia.

The inquiry is due to report by October 9 but the parliamentary committee has indicated it intends to summon Joyce regardless of whether he returns before that date.

Thursday’s tense questioning followed a heated grilling of Joyce’s replacement at the head of Qantas, Vanessa Hudson, and the company’s chairman, Richard Goyder, on Wednesday.

McKenzie also formally invited King to front the probe, after it was revealed her office instructed a senior Transport Department official to not answer one of the inquiry’s questions about a meeting with 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 King’s 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 said.

“It is completely unacceptable.”

Also on Thursday, the inquiry found 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. He said there was a “high probability” of a sweetheart deal between Qantas and the government.

On Wednesday, Qatar Airways’ officials told the inquiry they would aim to have extra flights into Australia by Christmas if their request was granted.

Elsewhere, the inquiry heard that polling by RedBridge on the decision to deny Qatar Airways more flights found 56 per cent of those surveyed supported or strongly supported a boost to the Middle Eastern airline’s operations.

McKenzie said only 5 per cent strongly opposed the flights, joking that “was probably the Qantas board”.

“This indicates to me that the government is assessing why the Qatar Airways decision is still being talked about,” she said.

McKenzie said the polling was done between August 30-September 4.

-with AAP