After outbreaks of the highly contagious Delta strain across the country forced a lockdown in Sydney and fresh restrictions elsewhere, Australia’s COVID-19 response committee is holding an emergency meeting on Monday.

As officials deal with COVID-19 flare-ups in practically every state and territory, more than 20 million Australians, or almost 80% of the population, are currently under some sort of lockdown or COVID-related restrictions.

“I believe we are approaching a new phase of this epidemic, with the more contagious Delta strain,” federal Treasurer Josh Frydenberg said on Monday, adding that Australia is at a “critical juncture” in its fight against COVID-19.

The country’s chief medical officer would brief the national security committee, which is chaired by Prime Minister Scott Morrison, later Monday, Frydenberg said.

Over the weekend, Sydney, Australia’s most populated city and the capital of New South Wales (NSW), began a two-week lockdown.

Eighteen new local cases were reported in NSW on Monday, compared with 30 a day earlier, taking the total infections in the latest outbreak to 130 since the first case was detected nearly two weeks ago in a driver for overseas airline crew.

“We have to be prepared for the numbers to bounce around and we have to be prepared for the numbers to go up considerably,” NSW Premier Gladys Berejiklian told reporters in Sydney.

“We’re witnessing almost 100% transmission within homes with this strain.”

After the Delta strain of the virus was discovered in a fly-in, fly-out mine worker, a two-day lockdown in Darwin, which was supposed to conclude on Tuesday, was prolonged to Friday.

Following a similar measure by Western Australian officials for the state capital Perth, Queensland and South Australia restored required masks and prohibited home gatherings. Restrictions are still in effect in Melbourne, Victoria’s state capital, and Canberra, the nation’s capital.

Queensland reported two new locally acquired cases while Western Australia and Northern Territory detected one each.

A health alert was issued over the weekend for hundreds of passengers after an infected Virgin Australia cabin crew member worked on five flights covering Brisbane, Melbourne and the Gold Coast.

With slightly over 30,500 cases and 910 deaths, Australia has fared significantly better than many other industrialized countries in combating the spread of the coronavirus.

Prior epidemics have been contained by lockdowns, strict social distance measures, and rapid contact tracking, but the fast-moving Delta form has frightened officials.

Stay-at-home orders were broken by 44 people in NSW, including a pair of naked sunbathers who got lost in a national park after being spooked by a deer.

“Not only did they require police help to rescue them, but they also received a $1,000 ($759) ticket,” NSW Police Commissioner Mick Fuller told reporters.