The Australian state of Victoria declared a state of disaster and imposed new blocking measures after an increase in coronavirus infections.
Victorian Prime Minister Daniel Andrews said the restrictions would take effect on Sunday at 6 pm (9 am BST).
Under the new rules, residents of the state capital, Melbourne, will be subject to an evening curfew.
The order of stay at home in the city will be improved, giving residents fewer exemptions to leave the home.
Residents will not be able to travel more than 5 km from home, exercise will be restricted to once a day and one person will be able to shop for essential items each time.
After the initial success in suppressing the virus, Australia had fewer cases than many other countries, registering around 17,000 infections and 200 deaths.
But cases are rising rapidly in Victoria, accounting for many of Australia's new infections in recent weeks, prompting a return to blocking restrictions in early July.
On Sunday, the state registered 671 new cases of coronavirus and seven deaths. These increases brought the total to 11,557 infections and 123 deaths.
Andrews said the blocking measures introduced in Victoria – Australia's second most populous state – are working very slowly.
"We must do more. We must try harder. It is the only way to get to the other side of it," Andrews told a news conference.
Andrews said the changes to the blocking rules announced on Sunday will remain in effect until at least September 13.
What are the new restrictions?
Andrews said Melbourne will move to the fourth stage restrictions on Sunday, putting more limits on the movement of people.
This will include an evening curfew, which will be implemented in Melbourne from 8:00 pm to 5:00 am on Sunday.
The only reasons for leaving home during these hours will be work, medical assistance or care.
Melbourne residents will only be able to shop and exercise within 5 km of their home. Exercises outside the home will only be allowed for one hour at a time.
All students across the state will return to home learning centers and childcare centers will be closed.
Regional Victoria will move to the third phase restrictions starting on Thursday, which means that restaurants, cafes, bars and gyms will close at 11:59 pm on Wednesday.
To ensure that these rules are observed, the police will have additional powers, said Andrews.
"These are big steps, but they are necessary," said Andrews. "We have to limit the amount of movement, therefore limiting the amount of transmission of this virus. We have to suppress it."
Why did Victoria become the epicenter of Australia's outbreak?
For months, Australia felt optimistic about containing the Covid-19. The country's curve flattened rapidly four months ago, with the application of mandatory hotel locks and quarantines for people entering the country.
Previously, most cases came from travelers returning from abroad, but the resurgence of the virus in Melbourne proved to be a major setback for the country.
Local broadcasts have become an important source of infections, putting the authorities on the back foot.
In early July, some 300,000 people were ordered back into confinement amid a military operation to "surround" ten postal codes in the center of the outbreak.
Then, about five million Melbourne residents were told to stay home for six weeks.
Andrews initially identified the source of many infections for security guards who allegedly violated the blocking rules while overseeing hotel quarantines.
Health experts say the relaxation of the rules, complacency in social detachment and sheer bad luck contributed to Victoria's rise in the cases.
Now, Andrews says the current rate of transmission from the community – including "mysterious cases" that cannot be traced back to work or home – is very high.
"And they tell us that, based on the current figure, cases can start to drop, not in days or weeks, but in months," said Andrews. "This is not something I am willing to accept."