Australia's No. 2 airline will ground the equivalent of 53 aircraft from its fleet, including all of its widebody jets.

"We have entered an unprecedented time in the global aviation industry, which has required us to take significant action to responsibly manage our business while balancing traveller demands and supporting the wellbeing of Australians," Virgin Chief Executive Paul Scurrah said in a statement.

"Wherever possible, we will aim to avoid redundancies by fast-tracking measures such as the use of accrued leave, leave without pay and redeployment," he said of the impact on staff.

Australia and New Zealand over the weekend said all international arrivals would need to self-isolate for 14 days, in a move that also led rivals Qantas Airways Ltd and Air New Zealand Ltd to make drastic cuts to capacity.

Virgin is in the weakest financial position of the three carriers. S&P Global Ratings downgraded its credit rating on Virgin to B- and placed it on creditwatch negative.

(Reporting by Jamie Freed; Editing by Sandra Maler and Grant McCool)