CANBERRA, Sept. 6 (The Guardian) - Australia will buy 84.8m vaccine doses at a cost of $1.7bn if two promising Covid-19 vaccine candidates prove successful, under deals for free access for Australians negotiated by the Morrison government.

The deals promising onshore manufacture of the University of Oxford vaccine by AstraZeneca and the University of Queensland vaccine by CSL will be announced by Scott Morrison with the health minister, Greg Hunt, and the science minister, Karen Andrews, on Monday.

The AstraZeneca deal could see 3.8m doses of the Oxford vaccine available as early as January and February 2021, with the UQ vaccine to follow in mid-2021.

The University of Oxford vaccine has entered phase three trials in the UK, Brazil, South Africa and the US. It has generated strong immune responses and no significant safety concerns to date.

The UQ vaccine is in pre-clinical testing, being used on 120 adults in Brisbane, and has shown promise in animal trials. Both vaccines are likely to require two doses per person – an initial dose and then a booster.

More than 95% of the vaccine doses will be manufactured in Melbourne, an advance on the position in August when the CSL chief financial officer warned it was too early to say if Australian manufacture was possible.

In a statement, the prime minister said: “Australians will gain free access to a Covid-19 vaccine in 2021 if trials prove successful.”

“By securing the production and supply agreements, Australians will be among the first in the world to receive a safe and effective vaccine, should it pass late-stage testing,” Morrison said.

“There are no guarantees that these vaccines will prove successful, however the agreement puts Australia at the top of the queue if our medical experts give the vaccines the green light.”

In August, the Morrison government announced a heads of agreement with AstraZeneca, prompting criticism from the opposition that a formal agreement had not been signed. Labor said Australia was lagging well behind the US and UK.

The announcement also caused confusion when Morrison was forced to clarify the vaccine would not be compulsory after earlier suggesting it would be “as mandatory as you can possibly make”.

Hunt said on Sunday night: “Any decisions regarding vaccines will be based on the advice of the Australian technical advisory group on immunisation and other experts, and will be contingent on a vaccine meeting all requirements with regard to testing and safety.”

“While the government supports immunisation, it is not mandatory and individuals maintain the option to choose not to vaccinate,” the health minister said.

The Australian government would purchase 33.8m doses of the Oxford vaccine and 51m doses of the UQ vaccine.

The Australian government has suggested it would also play a role in helping achieve early access to the vaccines for countries in the Pacific, as well as regional partners in south-east Asia.

Both agreements allow for additional orders to be negotiated and for doses to be donated or on-sold (with no markup) to other countries or international organisations. If both vaccines are successful, Australia will have around 30 million spare doses.