Sydney's Covid-19 infections have hit a daily record, putting parts of the health system under pressure, officials said, calling for vaccinations to be stepped up to stem the tide of hospital admissions.

Despite two months of lockdowns in Sydney, New South Wales (NSW) state reported 919 new cases amid a growing Delta variant outbreak, taking Australia's daily case numbers to a new pandemic high just below 1,000.

A total of 113 people in the state are in intensive care, with 98 of those unvaccinated.

"This highlights ... the fact that vaccination is the key. We need to increase those vaccine coverage levels," NSW Chief Health Officer Kerry Chant said during a televised media briefing in Sydney, the state capital.

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