* Victoria recorded 45 new virus cases and five further deaths, taking the state's toll to 750 and the national toll to 837.
* A virus cluster linked to five households in Melbourne's southeast has grown to 34 cases. The household members breached 5km travel restrictions to visit each other.
* Victoria's 14-day rolling infection average continues to improve, with 42.7 for Melbourne and 2.3 for regional Victoria.
* The states have agreed to a staged increase to the number of weekly international arrivals. The overall cap will rise from 4000 to about 6000 over the next two weeks.
* NSW will take an extra 500 overseas returning passengers from September 27.
* Queensland and WA will take an extra 200 Australians returning from overseas from September 27.
* Queensland will lift its weekly intake by a further 300 from October 4, with WA moving to the same position on October 11.
* Extra defence force personnel will help the states run hotel quarantine.
* Mandatory collection of information - such as name, email, mobile phone number and state of residences - will be rolled out for domestic air passengers from October 1.
* Boarding school students will be able to come home for the school holidays, under new medical advice.
* ACT residents will be able to fly to Queensland from September 25 unless they have visited a COVID-19 hotspot.
* WA will start testing wastewater for COVID-19 within the next month.
* Follow-up wastewater testing in southern Queensland has come back negative for coronavirus after fragments were detected in an earlier sewage test.
* Tasmania could reopen its borders to coronavirus-safe states and territories, except for Victoria, by the end of October, several months ahead of schedule.
* Melbourne's "ring of steel" to protect the regions from virus spread is sparking traffic delays, with a long line of vehicles seen on the road out to Geelong.
* September 14 to September 27 - stage four lockdown for Melbourne with some changes, including curfew moving back an hour to 9pm.
* September 27 - NSW, Queensland and WA will start taking more international arrivals
* September 28 - if average daily cases are 30-50 in metro Melbourne over the previous 14 days the city will move to the 'second step', including increased limits for public gatherings and a staged return to school for some students.
* October 26 - Tasmania's state of emergency due to expire. In Melbourne, the overnight curfew will be dropped if over the previous fortnight the average number of new cases falls below five and there are fewer than five cases from an unknown source.
* November - Victoria's hotel quarantine inquiry report due.
* November 23 - If there are no new cases for 14 days in Melbourne the city will move to the 'last step'. That includes all retail shops opening, public gatherings of up to 50 people allowed outdoors, and up to 20 visitors at a time allowed into a home.
AUSTRALIAN CORONAVIRUS NUMBERS
* There were 51 new cases in Australia - 45 in Victoria, six in NSW. Victoria announced an additional five deaths.
* The national death toll is 837: Victoria 750, NSW 54, 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 30,358,098
* Deaths: at least 950,636
* Recovered: at least 22,046,488
Data current as of 1730 AEST September 18, taking in federal government and state/territory government updates, Worldometer and Johns Hopkins Coronavirus Resource Centre.
© AAP 2020