LATEST COVID-19 DEVELOPMENTS:
* Victorian authorities have vowed to test hotel quarantine staff no longer working in the program after a Melbourne man linked to the Australian Open tested positive to COVID-19.
* The 26-year-old from Noble Park returned a negative test after working his last shift at the Grand Hyatt hotel on January 29, but later developed symptoms and went for a test on his own accord.
* Victoria's Deputy Chief Health Officer Allen Cheng said health authorities would expand the daily testing regime for hotel quarantine staff to cover those who aren't working.
* Two of the man's close household contacts have tested negative, while health authorities have been able to reach 19 of the 20 people identified as close contacts.
* A further 600 casual contacts also have been told to isolate and get tested, as have 520 tennis players, officials and support staff.
* Melbourne Park matches were suspended on Thursday, but will resume on Friday and tournament director Craig Tiley said the Open would go ahead as planned from next Monday.
* A number of states have introduced testing requirements for people travelling from Victoria, including NSW, South Australia, Tasmania, Queensland and Western Australia.
* Western Australia's hotel quarantine rules will be further tightened as much of the state prepares to emerge from lockdown.
* The state posted a fourth consecutive day of no new community COVID-19 cases, paving the way for metropolitan Perth, the Peel region and South West to almost certainly conclude their lockdown at 6pm on Friday.
* WA's planned re-categorisation of Victoria to "very low risk" on Friday was also put on hold, meaning incoming travellers will still need to quarantine for 14 days.
* The Northern Territory declared parts of Melbourne as COVID-19 hotspots over the Victorian hotel quarantine worker's case.
* Six people who came to Queensland from the Melbourne hotel at the centre of a separate case of COVID-19 transmission between guests are being sought for testing.
* Five others in NSW who recently spent two weeks at the Victorian quarantine hotel were also condemned to another fortnight-long isolation stint.
* South Australia will take charge of a new hotel in Adelaide next week as it moves to open a dedicated COVID-19 facility for people confirmed to have the virus.
* Prime Minister Scott Morrison rebuffed calls for a federal quarantine program despite another breach sparking fears of a fresh coronavirus outbreak.
* Australia has struck a deal for 10 million more doses of the Pfizer coronavirus vaccine, doubling the country's supply.
AUSTRALIAN CORONAVIRUS NUMBERS:
* Nine new virus cases were recorded in Australia on Wednesday; three in Victoria, three in NSW, two in WA and one in the NT. All but one were diagnosed in hotel quarantine.
* The national death toll is 909: Victoria 820, NSW 56, Tasmania 13, WA 9, Queensland 6, SA 4, ACT 3. (Two Queensland residents who died in NSW have been included in the official tolls of both states).
GLOBAL CORONAVIRUS NUMBERS:
* Cases: at least 104,389,000
* Deaths: at least 2,268,000
* Recovered: at least 58,001,000.
Data current as of 1830 AEDT on February 4, taking in federal and state/territory government updates, Johns Hopkins Coronavirus Resource Centre figures.