Prime Minister Scott Morrison says the federal and NSW governments are finalising how cashflow support for businesses in that state will work.

"We're moving swiftly, but you've got to make sure you've got that design right so it's simple, very simple, for businesses and it's rapid and is supported by the banks as well," he told Sky News on Monday.

Mr Morrison also defended a graphic ad showing a young women struggling to breathe after contracting COVID-19.

"It was only a few weeks ago that our very critics were saying that the advertising needed to be stronger, far stronger," he said.

The ad has been broadcast in Sydney as the city struggles with its growing outbreak, reporting 112 new cases on Monday.

There are 63 COVID-19 patients in hospital in NSW. Of those, 14 are under the age of 35 and 18 are in intensive care.

NSW Chief Health Officer Kerry Chant said these numbers dispelled the myth young people would not get sick from the virus.

The state's mass vaccination hubs and pharmacies will now start offering AstraZeneca vaccines to people aged over 40.

Vaccine task force leader Lieutenant General John Frewen urged people aged under 40 living in hotspot areas to talk to their doctor about getting the AstraZeneca vaccine, despite Pfizer being preferred for that age group.

Lt Gen Frewen said people in southwest Sydney needed to weigh up the risks of getting coronavirus against the vaccine advice.

"Those people between 18 and 40 need to make a decision now about whether they want to take their chances with the Delta virus or whether they want to get down, have a discussion with their GPs and get AstraZeneca," he said.

Public health expert Bill Bowtell demanded the "insensitive" coronavirus ad be taken down.

"It would have been far better to have a real person, real people, who have either had COVID or recovered from it, or regrettably there are thousands of families in Australia who have lost people to COVID," he said.

"That's honest, that's truthful, that's authentic and that has impact."

Labor frontbencher Tanya Plibersek also criticised the decision to use a young woman sick with the virus, considering the age group was not yet eligible for vaccination.

Meanwhile, two million medical-grade masks from the national stockpile are being sent to primary health networks across Sydney.

Gloves, gowns and goggles will also be distributed.

With no end in sight for Sydney's lockdown, small businesses warn their reduced revenues aren't enough to survive and they need much more support.

Cafes, bars and pubs are limited to offering takeaway and delivery.

Federal disaster relief payments worth up to $500 a week are available for people put out of work, while NSW has committed $1.4 billion for businesses.

Australian Associated Press