Hundreds of Melbourne train commuters have been ordered to isolate after being potentially exposed to coronavirus by an infected returned traveller.
The Department of Health has issued an urgent health alert after a Melbourne man tested positive after contracting the virus while in hotel quarantine in South Australia.
He flew home to Melbourne and travelled across the city on several trains last Friday night not knowing he had the virus.
Anyone who caught the 5.28pm Craigieburn to Southern Cross service on Friday May 7, or the 10.20pm Flinders Street to Craigieburn service on the same night, must get tested and isolate immediately until they receive a negative test.
'If you were on this service – in any carriage, and alighting and departing at any station – follow the health advice,' a statement read.
'If you travelled around this time but are unsure about which service you caught, please get tested.'
The two Metro Trains services listed have been declared tier two sites, which means commuters must remain in isolated until they return a negative test.
The infected man travelled from Flinders Street station (pictured) to Craigieburn on May 7
Flinders Street, Southern Cross and Craigieburn stations have all been declared Tier 3 exposure sites, which means anyone who was at any of these stations on May 7 must monitor for COVID symptoms.
The man, aged in his 30s, arrived home in Wollert in the Melbourne north on Tuesday May 4 before developing symptoms over the weekend.
He was tested on Monday after his condition worsened and produced a positive result on Tuesday morning.
The man had arrived in Australia from India, travelling through the Maldives and Singapore before arriving in South Australia.
New South Wales and Queensland are on high alert after the latest positive Covid case in Victoria.
An online declaration form will be mandatory to apply for Victorian visitors heading into those states, which applies from 6am on Wednesday, May 12 in NSW and 1am Thursday, May 13 in the Sunshine State.
'People arriving in New South Wales from the Greater Melbourne area must complete a declaration (form) which confirms they have not attended a venue of concern,' NSW Health said.
'If any travellers have attended any of the identified venues, they must contact NSW Health immediately.'
Some of the identified venues in Greater Melbourne include the likes of Bayside City, Frankston City, Knox City and Mornington Peninsula Shire.
A similar announcement emerged from the Queensland Premier on Tuesday night.
'From 1am Thursday 13 May, anyone arriving into Queensland who has been to any of the locations in Greater Melbourne must go into hotel quarantine for 14 days,' Ms Palaszczuk said.
'Anyone in Queensland prior to 1am Thursday who has been to any of the locations is also asked to quarantine at their home or arranged accommodation and also get a Covid-19 test.'
The message from NSW Health (pictured) confirming people arriving in the state from the Greater Melbourne Area from 6am onwards from May 12 must complete a declaration form stating they have not attended a venue of concern
The full list of Greater Melbourne Council areas:
Banyule City, Bayside City, Boroondara City, Brimbank City, Cardinia Shire, Casey City, Darebin City, Frankston City, Glen Eira City, Greater Dandenong City, Greater Geelong City, Hobsons Bay City, Hume City, Kingston City, Knox City, Macedon Ranges Shire, Manningham City, Maribyrnong City, Maroondah City, Melbourne City, Melton City, Mitchell Shire, Monash City, Moonee Valley City, Moorabool Shire, Moreland City, Mornington Peninsula Shire, Murrindindi Shire, Nillumbik Shire, Port Phillip City, Stonnington City, Whitehorse City, Whittlesea City, Wyndham City, Yarra City, and Yarra Ranges Shire.
Source: NSW Health
The infected Melbourne man was staying in a room adjacent to a positive case in the Playford medi-hotel and is believed to have contracted the virus in the final days of his quarantine following his last test.
South Australia's Chief Public Health Officer Professor Nicola Spurrier said the man was not believed to be infectious when he caught the flight back to Melbourne.
The man tested negative to his mandatory tests while in hotel quarantine and authorities believe he only became infectious after landing in Victoria.
Victorian Health Minister Martin Foley confirmed the man's re-test again came back positive on Tuesday afternoon but said his three household close contacts have returned negative tests.
A man has tested positive for coronavirus at his Melbourne home after serving his mandatory two weeks hotel quarantine in South Australia
Testing will continue across NSW after a man in Melbourne returned a positive reading for Covid in Victoria in Tuesday (pictured testing at Bondi Beach in Sydney's east)
He also confirmed there are three tier one areas of exposure, which mean anyone at the venues must immediately self-isolate, get tested and quarantine for 14 days.
There were also three tier two exposed venues, where anyone present must immediately get tested and isolate until they return a negative result.
Victoria's Chief Health Officer Brett Sutton says it was 'absolutely the case' that the man contracted the virus while serving his hotel quarantine in South Australia but said there were positives that his close contacts had produced negative tests.
'The early encouraging sign is the household close contacts are all negative given he would've been infectious likely since the 6th [of May].'
He says they have not yet released his flight number or the airport as areas of exposure because at this stage they don't believe the man was infectious while on the flight.
High exposure sites in Melbourne
Curry Vault Indian Restaurant and Bar
Indian Gate Spices and Groceries - Unit 14 C/560-590 High Street - 5pm and 6pm on Saturday, May 8
TIC Group - Rear warehouse section -214 Blackshaws Road, Altona North - All day, Thursday May 6
Anyone that has been at the exposure sites during the reported times must also immediately contact the state's coronavirus hotline on 1800 675 398.
More than two dozen workers at a Melbourne CBD health company were sent home as a 'precaution' after a potential coronavirus scare on Tuesday morning.
The workers at Citadel Health were sent home from their office on the city's busy Collins Street after one of the employees was notified as being a close contact of the Wollert man.
A spokesman for Citadel Health confirmed staff had been sent home to Daily Mail Australia but that their employee who was a close contact to the infected man had returned a negative result.
Victoria Health are now conducting a 'full public health response' into close contacts and possible hotspots.
Face masks remain mandatory on public transport in NSW (pictured commuters at Wynyard Station in Sydney's CBD)
'Further testing has been urgently arranged to confirm the diagnosis,' the Victorian Department of Health said on Tuesday.
'Until that time, the Department is treating this as a positive case and acting accordingly.'
The man and his household of three close contacts will remain in isolation for a further two weeks as is the incubation period with the virus.
'Until then, the department is treating this as a positive case and acting accordingly,' the department said.
'The individual is being interviewed and exposure sites are being verified.'
The man and his close contacts are all currently isolating while they await further testing