The coronavirus pandemic will bankrupt almost all of the world's airlines in a matter of weeks, Australian aviation experts say.

With passengers scrambling to cancel their flights and carriers grounding their services, airline analysis and consulting firm CAPA Centre for Aviation warned most airlines worldwide will be bankrupt by May unless urgent action is taken.

'As the impact of the coronavirus and multiple government travel reactions sweep through our world, many airlines have probably already been driven into technical bankruptcy, or are at least substantially in breach of debt covenants,' CAPA said in a statement on Monday.

Prime Minister Scott Morrison has advised Australians to reconsider overseas travel and all international arrivals will be forced to self-isolate for 14 days as COVID-19 continues to spread across the globe.

The coronavirus pandemic will bankrupt almost all of the world's airlines in a matter of weeks, Australian aviation experts say. Pictured: Travellers wear face masks in China

Prime Minister Scott Morrison advised Australians to reconsider the need for overseas travel and all international arrivals will now be forced to self-isolate for 14 days. Pictured: A Qantas plane in the sky

'Cash reserves are running down quickly as fleets are grounded and what flights there are operate much less than half full.

'Forward bookings are far outweighed by cancellations and each time there is a new government recommendation it is to discourage flying.

'Demand is drying up in ways that are completely unprecedented. Normality is not yet on the horizon.'

CAPA said coordinated government and industry action is immediately needed to avoid a 'catastrophe'.

But CAPA says the current government response is 'fragmented' as it is along national lines.

'As things stand, the likely tepid response to the airline crisis will equally be fragmented and nationally based. It will consist mostly of bailing out selected national airlines,' CAPA said.

'If that is the default position, emerging from the crisis will be like entering a brutal battlefield, littered with casualties.'

Virgin Australia's shares crashed 12 per cent on Monday and credit agency Standard & Poor's dropped the rating of its debt from B+ to B-.

With passengers scrambling to cancel their flights and carriers grounding their services, airline analysis and consulting firm CAPA Centre for Aviation has warned most airlines across the globe will be bankrupt by May. Pictured: The entry to departure gates at Sydney International Airport

Virgin Australia's shares crashed 12 per cent on Monday and credit agency Standard & Poor's dropped the rating of its debt from B+ to B-. 'The company's operating environment may be deteriorating at a faster pace than Virgin Australia can implement initiatives to protect cash generation and balance sheet health,' S&P said in a statement

'The company's operating environment may be deteriorating at a faster pace than Virgin Australia can implement initiatives to protect cash generation and balance sheet health,' S&P said in a statement, Sydney Morning Herald reported.

Foreign Affairs Minister Marise Payne was asked on ABC Radio if the government would support Qantas and Virgin amid the COVID-19 outbreak.

'Yes. We've already, of course, reported and announced a very significant economic response in the last week and that is about protecting the economy, trying to maintain confidence to support investment and importantly to keep people in jobs,' she said.

'But as this progresses, I am sure there will be other matters which need to be considered – maybe the ones that you have raised,' she said.

Qantas Group on Sunday announced customers with new and existing bookings on domestic and international flights would be given the option to cancel and receive travel credit.

'Qantas and Jetstar have introduced greater flexibility for customers wishing to change their travel plans, following increased travel restrictions being implemented by various governments around the world due to the evolving coronavirus situation,' Qantas Group said in a statement.

CAPA advises that coordinated government and industry action is immediately needed to avoid a catastrophe. Pictured: Travellers at London's Heathrow Airport

The changes are available for Qantas, Jetstar and QantasLink flights and apply until March 31 for travel until May 31.

On Monday, Virgin Australia announced it was providing travellers with 'more options' to change their bookings amid coronavirus travel restrictions.

Chief Customer Experience Office Danielle Keighery said: 'We understand that these new restrictions may affect guests' travel plans. This is why we've removed change and cancellation fees so guests can have more flexibility with their upcoming travel.

'We want guests to have peace of mind when booking with us, and this flexibility will extend to any new bookings made for travel between now and 30 June.

'Our team is working around-the-clock to help our guests with any changes to their travel plans and we thank our guests for their patience during this time.'

Mr Morrison has warned Australians will likely have to change their way of life for a least six months as parts of the nation's response to COVID-19.

'This will be a difficult six months. It could be longer. It could be sooner than that,' he told ABC radio on Monday.

Pictured: A family arrived at Gold Coast airport with face masks amid fears of COVID-19 spread

Queensland Nationals senator Susan McDonald has become the second federal politician to test positive for the virus, after Home Affairs Minister Peter Dutton was diagnosed last week.

Senator McDonald had not been in direct contact with Mr Dutton and had not been overseas, but had been in Canberra last week.

The total number of cases in Australia has reached more than 360, while the deaths of a 77-year-old and 90-year-old take the toll to five.

The country's deputy chief medical officer Paul Kelly said 80 per cent of cases would be mild and not require hospitalisation.

Anzac Day services and marches have been cancelled in NSW, Western Australia and Tasmania with other states reviewing their commemorations, while some schools around the country are planning to close.

Non-essential gatherings of more than 500 people have been banned, all people arriving from overseas must quarantine themselves for 14 days, and cruise ships are barred from Australian ports for at least 30 days.

People arriving in Australia will be allowed to transit to their home state if they are well upon arrival, but not if they're sick.

The government last week announced $17.6 billion in support for small and medium businesses and cash payments to people on welfare, but recognises there will be a deeper-than-expected economic impact

The nation's top medical officers met on Monday to consider whether leaders should place further restrictions on indoor gatherings.

Meanwhile, the prime minister, Treasurer Josh Frydenberg and Finance Minister Mathias Cormann considered further economic measures.

The government last week announced $17.6 billion in support for small and medium businesses and cash payments to people on welfare, but recognises there will be a deeper-than-expected economic impact.

Tourism Minister Simon Birmingham acknowledged the impacts on travel and the tourism industry are dire.

'This is going to go on for some time and I fear it will get worse before it gets better,' he told radio station 4CA in Cairns.

Queensland, Victoria, the ACT and South Australia have declared a state of emergency while Tasmania will force all people coming to the island state to fill out passenger arrival cards.