"It is my personal view that you are now obstructing the committee," he told Treasury secretary Stephen Kennedy, threatening to start using freedom-of-information laws to access the information.

"All the modelling your department does is done on the public coin and for public purposes," Senator Patrick told Dr Kennedy.

"The public has a right to see what it is that your department has done and I think it is disrespectful for Treasury to withhold the information from the public."

Dr Kennedy said he was guided by advice from the Department of Prime Minister and Cabinet about which documents should be considered "cabinet in confidence".

The inquiry sought Treasury scenarios and modelling work on the economic response to the coronavirus impact.

The government has announced stimulus measures in three tranches, totalling $215 billion, on top of $110 billion in loan guarantees. The measures are largely aimed at businesses, and include tax incentives to buy equipment and retain staff, a wage subsidy for apprentices, and the biggest single initiative, the JobKeeper wage subsidy, for most workers in businesses impacted by the shutdown. The JobSeeker payment has also been doubled, and the government is handing two lots of $750 in cash to welfare recipients and pensioners.

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Committee chairwoman Senator Katy Gallagher told Dr Kennedy the committee did not share the view that he was obstructing the inquiry.

While Dr Kennedy refused to release the modelling to the Senate inquiry, he provided a briefing from the end of January on the likely economic impacts of the virus. At the end of January the focus was still on China, with the virus impact largely confined to China. Officials told Treasurer Josh Frydenberg that it was too early to quantify the economic impacts - but they used the SARS outbreak in 2003 as a guide.

The Chinese economy in January was four times larger than in 2003, so any flow-on impacts to the global economy would be larger, the January 30 advice said. In 2003 China accounted for 8 per cent of Australia's trade; in January 2020 it was 25 per cent.

"However, China is also better placed to deal with a disease event," the advice said, pointing to the severe shutdown in China.

SARS reduced growth in Australia's gross domestic product by 0.2 per cent.

More to come

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