Prime Minister Scott Morrison said the agreement would mean the number of Pfizer doses arriving in Australia during September would double.

"From Downing Street to Down Under, we are doubling down on the Pfizer doses here in Australia this month," he told reporters in Canberra.

The extra vaccines will be distributed to states and territories based on population.

Health Minister Greg Hunt said vaccination coverage targets of 70 and 80 per cent were now within sight.

"The burden and balance of vaccination in Australia will have moved forward two months from October and November to August and September," he said.

The prime minister said about half of the more than 20 million doses administered nationally were AstraZeneca.

"I want to encourage people if you are booked for AstraZeneca today, go and get it," Mr Morrison said.

"The best dose you can get today is the dose you can get today."

Earlier in the week, Australia clinched a swap deal with Singapore for 500,000 Pfizer doses to be repaid in December.

Last month, Poland agreed to send one million doses to Australia.

Mr Morrison said the UK and Singapore agreements broke the back of supply issues.

"In terms of additional doses, yeah I'm up for them where they can be secured and I will pursuing those deals."

About 36 per cent of the population aged 16 and above is fully vaccinated against coronavirus which is spreading across NSW, Victoria and the ACT.

Australia's rollout remains well behind almost all of the developed world but momentum has grown in recent weeks.

Australian Associated Press