Victoria Premier Daniel Andrews said the state will return to stage 4 lockdown from 11.59 p.m. on Friday night to prevent further community transmission of a highly infectious Covid-19 strain, reports Xinhua news agency. 

Under the rules, Victoria residents can only leave their homes for four reasons -- shopping for essentials; care and caregiving; exercise; and essential work. 

Exercise and shopping will be limited to 5 km from home and face masks will need to be worn indoors and outdoors. 

No home visitors will be allowed. 

Religious gatherings and weddings will not be permitted, and funerals will be limited to 10 people. 

All non-essential retail, gyms, pools, community centers, entertainment venues and libraries will close. Cafes and restaurants will only be able to offer takeaway. 

"I know this is not the news Victorians wanted to hear today, I know this is not the place we want to be in... We have to make difficult decisions to maintain what we have built," Andrews said on Friday. 

"If we wait for this theory that it might be out there, there might be more cases than we know about, it would be too late, and then we would face the chance of being locked down until a vaccine is rolled out." 

Covid-19 cases linked to the Holiday Inn hotel at Melbourne Airport have grown to 13, with five new cases confirmed on Thursday. 

Six of the cases were infected with the highly contagious British Covid-19 strain, and the "working assumption" is that all 13 cases may be the same strain. 

Meanwhile, the Brunetti cafe in Terminal 4 at the Melbourne Airport was listed as an exposure site on Friday morning after it was visited by an infected person on February 9, prompting urgent responses from other states and territories. 

Health authorities in New South Wales (NSW) are currently contacting approximately 7,000 people who entered the state from Victoria after attending these venues of concern, to ensure they are aware of the requirements. 

Meanwhile, anyone in NSW who had been in Victoria after January 29 should remain at their home or place of residence for the five-day period announced by the Victoria government. 

Queensland will close its borders to 36 local government areas for a period of 14 days from 1 a.m. on Saturday. 

Some 1,500 people in Queensland who had travelled through terminal 4 of Melbourne Airport would need to go into 14 days quarantine. 

Tasmanian Premier Peter Gutwein also declared all of Victoria "high risk" from midnight Friday and non-Tasmanian residents travelling from the state will be denied entry.