Escalating travel bans in Australia and New Zealand could block access to vital coronavirus research and knowledge, experts have warned.

The two countries have closed their borders to all non-residents, just days after imposing new rules requiring all people arriving from overseas to self-isolate for a fortnight.

While the self-quarantine requirements were widely supported, the entry ban defies expert advice. Critics of travel bans say they can create more problems than they solve, partly because they impede the flow of medical supplies and expertise that could prove pivotal.

Mary-Louise McLaws, a professor of epidemiology at UNSW Sydney, said Australia lacked experience of a ¡°large catastrophic¡± outbreak.

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¡°China has had it twice,¡± she added. ¡°They¡¯ve learnt from Sars [severe acute respiratory syndrome] and they¡¯ve done an absolutely stellar job with Covid-19. We could use their epidemiological and medical expertise.¡±

She said Chinese authorities recognised that the country was at a ¡°tipping point¡± as it gradually eased restrictions on movement and commerce. ¡°They¡¯re doing it very carefully and we need to learn from that.¡±

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NZ prime minister Jacinda Ardern said travel restrictions had been escalated because overseas visitors were not adequately self-isolating. ¡°That is an unacceptable risk that we must end,¡± she said.

Australian prime minister Scott Morrison said the new lockdown was consistent with earlier decisions. He said 80 per cent of Australia¡¯s coronavirus cases had either contracted the virus overseas or had direct contact with recent returnees.

But the most recent on travel bans from the chief advisory body, the Australian Health Protection Principal Committee, was that the government should maintain the existing restrictions. The AHPPC had earlier ¡°further widespread application of travel restrictions¡±.?

Peter Sheehan, research director at Victoria University¡¯s Institute of Strategic Economic Studies, said the government should consider gradually easing bans on travel from countries where the virus was being contained ¨C with China a pertinent example.

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According to the most recent World Health Organisation , China recorded about half as many new infections as Australia, one-tenth of the UK figure, one-fiftieth of the US and one-hundredth of Italy on 17 March.

Victoria University of Wellington vice-chancellor Grant Guilford, an avowed critic of travel bans, said they were driven by politics rather than good health policy. He said governments were keen to cultivate an impression that they were ¡°protecting the best interests¡± of an anxious populace.

Professor Guilford said Western countries could benefit from understanding the expertise, technology and ¡°quite draconian methods¡± the Chinese had employed to suppress the outbreak.

¡°There¡¯s a sense of pride in the way they¡¯ve contained the infection,¡± he continued. ¡°The world learns every time one of these things happens. I think they¡¯d be pleased to help the world with their knowledge, if we were humble enough to accept it.¡±

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Ms Ardern said the NZ ban applied to people, not products. But Professor Guilford said authorities choked the supply of drugs and medical equipment when they closed the door to travellers, because there were fewer aircraft to ferry goods.

Professor Sheehan said: ¡°We shouldn¡¯t let this impede the flow of what we can learn. China now has the best reservoir of knowledge in the world about this disease, and how to handle it.¡±

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john.ross@timeshighereducation.com