Sydney's fast-growing coronavirus outbreak has become a "national emergency," state leaders said Friday, as Australia's largest city reported another record number of new infections.

Admitting a month-long lockdown had failed to stop a Delta-variant outbreak, the state of New South Wales pleaded for Canberra to urgently send more vaccines and resources.

Calling the outbreak a national emergency could pave the way for more federal government involvement in stemming the crisis.

"We have an obligation on behalf of the nation to contain the virus," said New South Wales premier Gladys Berejiklian. "There is no doubt that the numbers are not going in the right direction."

Just 12 percent of Australians have been fully vaccinated, thanks to problems with supplies of Pfizer jabs and scepticism about the safety of the AstraZeneca vaccine
Just 12 percent of Australians have been fully vaccinated, thanks to problems with supplies of Pfizer jabs and scepticism about the safety of the AstraZeneca vaccine AFP / Saeed KHAN

Her state on Friday reported 136 new cases, a record for this outbreak, which now totals 1,782.

With the virus "spreading everywhere" and half the country's 25 million people currently in lockdown, Berejiklian said the government must "refocus" its glacial vaccine rollout.

Just 12 percent of Australians have been fully vaccinated, due to problems with supplies of Pfizer jabs and scepticism about the safety of the AstraZeneca vaccine.

"We need, at least, more first doses of Pfizer," Berejiklian said, while warning Sydney's five million residents that restrictions could run until October.

A month-long lockdown has failed to stop a Delta-variant outbreak in New South Wales
A month-long lockdown has failed to stop a Delta-variant outbreak in New South Wales AFP / Saeed KHAN

But a request to channel vaccines to hard-hit areas was rebuffed by Prime Minister Scott Morrison.

"We're not going to disrupt the vaccination programme around the rest of the country," Morrison said, insisting his home city will make it through this crisis.

Berejiklian also announced non-essential workers in specific areas of Sydney would now be barred from leaving, tightening a lockdown that is almost certain to be formally extended next week.

"It is fairly apparent that we will not be close to zero (cases) next Friday," Berejiklian said. "We will have a clearer view next week on what August, September, and October look like."

Just 12 percent of Australians have been fully vaccinated, thanks to problems with supplies of Pfizer jabs and scepticism about the safety of the AstraZeneca vaccine
Just 12 percent of Australians have been fully vaccinated, thanks to problems with supplies of Pfizer jabs and scepticism about the safety of the AstraZeneca vaccine AFP / Saeed KHAN

Morrison on Thursday apologised for the country's slow vaccine rollout, admitting targets had not been met.

"I take responsibility for the vaccination programme. I also take responsibility for the challenges we've had," he said. "Obviously, some things are within our control, some things that are not."

With Sydney cases spiralling, Victoria state premier Dan Andrews called for a "ring of steel" to be thrown up around the city, banning any travel in or out.

In New Zealand, Prime Minister Jacinda Ardern announced that a travel bubble between the two countries would be suspended for at least eight weeks.

Australians will no longer have quarantine-free entry to New Zealand, and return flights will be arranged for New Zealanders in Australia.

"There are now multiple outbreaks, and in differing stages of containment, that have forced three states into lockdown," Ardern said.

"The health risk to New Zealanders from these cases is increasing... now is the time for a suspension to ensure New Zealanders aren't put at undue risk from Covid-19 and to ensure we retain our hard-won gains."

Quarantine-free travel between New Zealand and Australia began in April after more than a year of closed borders and was hailed by tourism operators as a "saviour for businesses".

However, New Zealand has several times since halted the bubble with individual states and territories as outbreaks erupted in Australia.