Parts of Sydney will go into lockdown today (Friday) as a coronavirus outbreak in Australia’s largest city continues to grow.

Health authorities have reported an additional 22 locally transmitted cases and imposed a week-long lockdown in four areas, saying people could leave their homes only for essential purposes, AP reports.

“If you live or work in those local government areas, you need to stay at home unless absolutely necessary,” said Gladys Berejiklian, the premier of New South Wales state.

She said the lockdown, which was due to go into effect just before midnight, would have a significant impact on businesses, especially in the central business district of the city of more than five million people.