Millions of Pfizer COVID vaccines will be available in Australia in coming weeks as batches arrive from Singapore and the UK.

A wave of COVID-19 vaccination doses is about to sweep Australia's states and territories.

The 500,000 doses of the Pfizer vaccine secured by the federal government from Singapore have been given the tick of approval by the Therapeutic Goods Administration and are being dispatched.

Deputy Chief Medical Officer Sonya Bennett also said the first instalment of four million Pfizer doses from the UK are also winging their way to Australia, with the rest due over the remainder of September.

She said the initial shipment was supposed to be 290,000 doses, but fortunately that will be 450,000 doses.

"So the additional supplies are really reassuring," Dr Bennett told reporters in Canberra on Sunday.

"We would just like to encourage all Australians, given the circumstances, to book in and go and get their first doses as soon as possible."

The additional supplies will support the national COVID-19 response plan to get to 70 and 80 per cent vaccination targets to enable restrictions to be eased.

So far, more than 35 per cent of the eligible population aged over 16 is fully vaccinated with two doses.

However, it would appear that the boundaries laid out in the plan are not set in stone.

"The national plan is designed to give us a framework on which to operate from," federal minister Stuart Robert told ABC's Insiders program on Sunday.

But he conceded the plan may change with circumstances.

"Look at the last 12 months, things have been shifting on a daily and weekly basis. A plan is always a basis for change, it has to be," he said.

Shadow treasurer Jim Chalmers jumped on the remarks, saying they have left the prime minister's campaign in tatters.

"Scott Morrison has said that we should open up at 70 per cent and 80 per cent at all costs," Dr Chalmers told reporters in Brisbane.

"(Treasurer) Josh Frydenberg has said that states should be punished for not opening up by the withdrawal of support payments."

But ACT Chief Minister Andrew Barr said flexibility has always been part of the plan that was agreed by the national cabinet, of which he is a member, and was pleased to see that Mr Robert had actually read the plan.

"At the bottom in a font larger than most other fonts in the plan is 'based on the current situation and is subject to change if required'," Mr Barr told reporters in Canberra.

NSW Premier Gladys Berejiklian will release her own COVID-19 modelling this week on the looming peak in the state's case numbers and hospitalisations.

"All the modelling indicates to us that the peak is likely to be here in the next week or two," the premier told reporters.

"The peak in hospitalisation and intensive care is likely to be with us in October."

The state reported 1485 new virus and three deaths on Sunday, bringing the toll in this outbreak to 126.

The three included a woman in her 50s and a man and a women in their 70s.

Victoria recorded a further 183 new virus cases on Sunday, 101 of which are linked to known cases and outbreaks.

The state's chief health officer Brett Sutton continues to urge more people to get vaccinated in order to hold back the "tsunami" of potential cases.

The third jurisdiction in lockdown, the ACT, reported 15 new cases, which was less than half of the record 32 reported the previous day.

Queensland recorded one new case, the mother of a four-year-old girl who had already tested positive to the virus.