Australia's New South Wales has reported one of the country's youngest deaths from Covid-19, as daily infections linger near a 16-month high despite the lockdown of five million people in Sydney entering its sixth week, Reuters reports.

The unnamed man in his 20s, who had no underlying health issues and was unvaccinated, died at his home in the city, authorities said. He deteriorated rapidly after earlier complaining of just mild symptoms, they added.

The man was ineligible for a Pfizer vaccine, as Australia limits that type for people over 40 amid tight supplies, while Canberra has only recently told people to take the AstraZeneca vaccine as cases swell, having previously limited it to people over 60.

The death highlights the risk facing Australia's largest city, which is struggling to contain an outbreak of the highly infectious Delta variant when fewer than 20 per cent of Sydney's residents are vaccinated.

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