Three Sydney archbishops have written to Prime Minister Scott Morrison expressing concern that a COVID-19 vaccine which Australia has signed a deal over is "ethically tainted".

The Australian Government announced last week that it had signed a deal to receive 25 million doses of a vaccine being developed by AstraZeneca and Oxford University should trials prove successful.

In a letter dated 20th August - the day after announcement, Catholic Archbishop of Sydney Anthony Fisher, Anglican Archbishop Dr Glenn Davies and Greek Orthodox Archbishop Makarios Griniezakis said they were "disappointed" the Australian Government had made a deal involving a possible vaccine that "makes use of a cell-line...cultured from an electively aborted human foetus".

They wrote that while some will have "no ethical problem" with using such tissue or believe it sufficiently removed from the abortion to be excusable, others will be "concerned not to benefit in any way from the death of the little girl whose cells were taken and cultivated, not to be trivalising that death, and not to be encouraging the foetal tissue industry".

The three archbishops sought assurances that the AstraZenica/Oxford University vaccine "will in no sense be mandatory", that no-one will be pressured to prescribe, dispense or have the vaccine "against their conscientious religious or moral beliefs" and that the government would ensure "an ethically uncontroversial alternative vaccine" be made available in Australia if achieved.

They added that "our churches are not opposed to vaccination" but are praying one that is not "ethically tainted" may be found.

In an article published in Catholic Weekly, Archbishop Fisher added that while he didn't think "it would be unethical to use this vaccine if there is no alternative available", he was "deeply troubled" by it.

Australia's Deputy Chief Health Officer Nick Coatsworth has responded by saying that people "can have every faith that the way they have manufactured the vaccine has been against the highest of ethical standards internationally".