Queensland Nationals Senator Susan McDonald issued a statement late on Monday saying she had begun "to feel unwell with a sore throat and a mild temperature " on Friday night so had gone to the Townsville Base Hospital emergency department where she had been tested for the virus.

"Unfortunately the test has today come back positive and I have now been admitted to hospital," she said.

She is not believed to have travelled overseas and she gave no information on how she might have contracted the virus, nor why she was tested given that testing is restricted to people who have been overseas or in contact with a known case.

Senator McDonald is on the Senate Rural and Regional Affairs and Transport committee, which is had a long list of inquiries underway. This week's meetings this week have all been cancelled.

Senator McDonald's office did not return calls but a Nationals spokeswoman said she understood the Senator had had no contact with other members of the parliamentary party while infectious and no one else needed to isolate.

With Parliament returning on Monday, March 23, some parliamentary passes have been suspended to limit the number of people allowed in the building, Speaker Tony Smith and Senate President Scott Ryan said.

Former parliamentarians, members of state parliaments, volunteers and sponsored pass holders won't be allowed into non-public parts of the building. People who are allowed to keep their passes are being asked not to sign in visitors unless the visit is essential, and public servants are asked to strictly limit their visits to Parliament House.

MPs and Senators have been asked to bring only essential staff to Canberra next week.

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The public galleries are also closed for the parliamentary sitting week and school groups and tours are cancelled. Events in the building have also been cancelled.

Otherwise, the public areas remain open.

Parliament House has also foreshadowed changed to the "management of staff and operations of the chambers and the wider building, including catering", including social distancing. And it has asked committees to use video for hearings, with witnesses appearing in person only if necessary, to close any hearings to the public, and to consider whether the hearings are essential.

With reports emerging on Monday that two people who shared a flight to Los Angeles with Home Affairs Minister Peter Dutton had tested positive to coronavirus, Deputy Chief Medical Officer Professor Paul Kelly said he was confident Mr Dutton was not infectious on the flight. But he might have contracted the virus on the flight.

"Whether he caught it on the plane or before that it's hard to know," Professor Kelly said. "We know that the incubation period for this particular virus is quite long - it can be up to 14 days, but mostly five to six days. He'd been back in Australia for six days by the time he became sick. So he was not infectious on that plane."

Mr Dutton flew to Los Angeles on the flight with the women who now have coronavirus on March 4. He returned on March 8; they arrived back on March 14.

Mr Dutton tested positive to coronavirus on Friday March 13. It is possible he contracted the virus on the March 4 flight, or while in the United States.

In the US, he met Donald Trump's daughter Ivanka Trump and other senior officials in the Trump circle, but health authorities in Australia insist he would not have been infectious before Wednesday March 11, so are focused only on the 24 hours before he started showing symptoms. Mr Dutton attended a cabinet meeting on Tuesday March 10 in Sydney, but his Cabinet colleagues are not considered at risk despite the cabinet room being scrubbed by people in hazmat suits on the weekend.

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