Under the deal, Australia would make and supply the vaccine - should it prove safe and effective - and provide it free to all Australians.
The agreement is expected to not only be a shot in the arm for the health response but a booster jab of confidence for the recession-hit Australian economy.
"The Oxford vaccine is one of the most advanced and promising in the world, and under this deal we have secured early access for every Australian," the prime minister said.
Mr Morrison admitted there was no guarantee the vaccine would be successful, so the government was continuing talks with other parties as well as backing Australian researchers.
The letter of intent with AstraZeneca, and a needle and syringe contract with Becton Dickinson, are the first announcements under a national COVID-19 vaccine and treatment strategy.
The vaccine strategy is expected to be worth billions of dollars.
The Oxford University trials are under way in the UK, Brazil and South Africa and are due to soon start in the US, running into early 2021.
But Australian medical advisers are aware of 167 vaccine candidates in pre-clinical and clinical trials, including 29 undergoing clinical trials in humans.
An expert group led by Health Department secretary Professor Brendan Murphy is examining all options to ensure Australia doesn't pin all of its hopes on one vaccine.
Australia is also in talks with the Gavi-led COVAX Facility, which aims to pool global resources to accelerate the development and distribution of vaccines.
Biotechnology company CSL said while development of the University of Queensland's vaccine candidate remained its priority, it was also in discussions with AstraZeneca and the federal government on providing local manufacturing support for the Oxford University-AstraZeneca vaccine.
"We are assessing the viability of options ranging from the fill and finish of bulk product imported to Australia through to manufacture of the vaccine candidate under licence," CSL said in a statement.
"There are a number of technical issues to work through and discussions are ongoing."
