Live breaking news: New Covid-19 cases in NSW, WA, QLD, lockdown in NT

Australia is grappling with an explosion in covid cases across several states with lockdowns, border controls and restrictions affecting millions.

Australia's Covid battle has significantly worsened in the past 24 hours, as multiple states and territories respond to new cases and expanding contacts. 

The Northern Territory, Western Australia and Queensland have joined New South Wales in implementing restrictions as health authorities battle surging Covid cases.

Four new cases connected to an infected miner in the NT has sparked a snap 48-hour lockdown in Darwin, Palmerston and Litchfield, with residents only allowed to leave their home for five reasons: to seek medical treatment, to purchase essential goods and services, for essential work, to undertake one hour of exercise or to give care.

In WA, a traveller from Sydney has also tested positive for what authorities believe is the Delta variant. As a result, the state has reinstated new restrictions across the Perth and Peel areas. 

Meanwhile, NSW has recorded a further 30 cases, with the total number of infections in the state currently at 102. Despite this, Premier Gladys Berejiklian said larger daily figures will likely be reported in the coming days. 

South Australia closed its border to the NT, Queensland, WA and the ACT, despite the latter having zero coronavirus cases.

This is how Sunday's news unfolded.