Home Affairs Minister Peter Dutton has tested positive for coronavirus.
Mr Dutton said in a statement on Friday he had been tested after waking up with a temperature and sore throat that morning.
"I feel fine and will provide an update in due course," he said.
Prime Minister Scott Morrison will not need to self-isolate, his office said, because his most recent contact with Mr Dutton was more than 24 hours before the minister showed symptoms.
Mr Dutton, one of the Coalition government's most senior ministers, said he contacted the Queensland Department of Health immediately after noticing the symptoms on Friday morning.
The Prime Minister's Office released a statement saying Mr Dutton had been isolated according to Queensland Health policies.
Queensland Health will trace Mr Dutton's recent contacts.
The Home Affairs minister attended Tuesday's meeting of the federal cabinet in person, and Thursday's meeting of the National Security Committee via video link.
"In advice provided to the Prime Minister this evening, the Deputy Chief Medical Officer has reiterated that only people who had close contact with the minister in the preceding 24 hours before he became symptomatic need to self-isolate," the Prime Minister's Office said.
"That does not include the Prime Minister or any other members of the cabinet."
On Saturday, Chief Health Officer Brendan Murphy said he had been with cabinet on Tuesday when Mr Dutton was there.
"I can assure you that Minister Dutton developed his symptoms yesterday morning, a long time after the Tuesday cabinet meeting. Our case definition across the board is that you are only a close contact if you have been in a close contact within 24 hours of someone becoming symptomatic or after they have become symptomatic," he said.
"No member of cabinet was in contact with minister Dutton within 24 hours of him becoming symptomatic, nor was I in fact in contact with him. So the Prime Minister was very, very clear to me that the cabinet and all the public officials follow the exact same public rule, public health rules as everybody else in the Australian community.
"If there had been a requirement for quarantine, he was insistent that government and cabinet follow those rules, so we just follow the normal public health advice, no-one had been in contact with the minister in that period."
Despite earlier saying he would attend the Cronulla Sharks NRL match on Saturday, media reports emerged on Friday night saying Mr Morrison had cancelled his attendance.
Mr Dutton's positive test result has also raised questions about his recent contacts at meetings in Washington earlier this month.
In a photo tweeted by the Australian Embassy in the US on March 7, he is shown standing next to Ivanka Trump and near US attorney-general William Barr.
Yesterday 🇦🇺 Home Affairs @PeterDutton_MP joins @IvankaTrump, Attorney General Barr & our five eyes partners 🇺🇸🇬🇧🇨🇦🇳🇿 to fight online child exploitation. We heard from 9 brave survivors & announced principles that technology companies should implement to protect children online pic.twitter.com/3ifeJnGJPI— Australia in the US 🇦🇺🇺🇸 (@AusintheUS) March 6, 2020
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