MELBOURNE - Australia's Delta outbreak appears to have levelled off, with more than half the country in extended lockdowns and vaccination rates starting to approach national targets, Health Minister Greg Hunt said on Monday.

Hunt said 80% of Australians will have had their first COVID-19 jabs this week, while the overall battle against the virus has been boosted by the arrival in recent days of 15,000 additional doses of treatment drug sotrovimab.

The Australian government wants all COVID-19 restrictions, including travel bans, to be lifted when 80% of the population above 16 is fully vaccinated. It expects that target will be reached in mid-November.

"There are important reasons for hope," Hunt told reporters in a televised press conference, pointing to a steep fall in new cases in New South Wales state, home to Australia's biggest city Sydney.

"Victoria, yes, it is a big challenge ... But we are beginning to see the flattening of the curve in Victoria," he said.

New South Wales on Monday reported 623 new cases and six deaths, down from more than 900 cases a day a week ago.

Victoria state reported 1,377 new COVID-19 infections, up from 1,220 on Sunday, but off a record high of 1,488 on Saturday. There were four new deaths.

Officials have blamed a recent spike in Victoria's cases on Australian Rules football final parties, in breach of strict lockdown rules the previous weekend. Nearly half of the new cases on Monday were people between the ages of 10 and 29.

The state's capital Melbourne, in the midst of its sixth lockdown, on Sunday reached a cumulative total of 245 days of restrictions since March last year, overtaking Buenos Aires as the city under the longest lockdown, according to local media.

Despite the current downtrend, experts have warned that cases are likely to rise again once the country emerges from lockdown, replicating the experience in other countries that vaccinated earlier.

New South Wales is due to start easing curbs from Oct. 11, the first Monday after it expects 70% of its population over 16 to be fully vaccinated, up from 67% now.

Victoria hopes to reach the 70% target, up from about 52% now, by Oct. 26.

GlaxoSmithKline and Vir Biotechnology's VIR.O sotrovimab has been shown to be effective in reducing hospitalization and death among high-risk COVID-19 patients when given early in the disease.

Hunt said he hoped another COVID-19 drug, a pill being tested by Merck & Co Inc, would be available in Australia in the first quarter of 2022.

(Reporting by Sonali Paul; Editing by Himani Sarkar and Richard Pullin) ((Sonali.Paul@thomsonreuters.com; +61 407 119 523;))