New Zealand Prime Minister Jacinda Ardern made a rare appearance at a top Australian government meeting Tuesday, as both countries moved a step closer to establishing a potential coronavirus-free travel corridor.

The proposal, known formally as the trans-Tasman Covid-safe travel zone, would allow residents to travel freely between the two neighboring nations, without a need for quarantine.

Ardern was invited to join the Australian national cabinet meeting by the country's leader Scott Morrison.

It was the first time a New Zealand leader had attended a meeting of Australia's national cabinet or similar gathering since the Second World War.

In a joint post-meeting press release, both Arden and Morrison promised to begin work on the scheme "as soon as it was safe to do so."

"A trans-Tasman Covid-safe travel zone would be mutually beneficial, assisting our trade and economic recovery, helping kick-start the tourism and transport sectors, enhancing sporting contacts, and reuniting families and friends," the statement said.

"We need to be cautious as we progress this initiative. Neither country wants to see the virus rebound so it's essential any such travel zone is safe. Relaxing travel restrictions at an appropriate time will clearly benefit both countries and demonstrates why getting on top of the virus early is the best strategy for economic recovery."

The national cabinet consists of all the leaders of Australia's eight states and territories as well as the Prime Minister, and is only assembled in times of national crisis.

"There is still a lot of work to be done before we can progress an idea like that, but it's obviously being floated because of the benefits it would bring," Ardern said Tuesday, after leaving the meeting.

Morrison said that Ardern had primarily been asked to join to share her experience tackling the coronavirus with Australia's state and territory leaders.

The discussion of a special travel arrangement comes as both Australia and New Zealand have made strong progress in bringing their local coronavirus epidemics under control.

There were no new cases of coronavirus in New Zealand on Tuesday for the second day in a row, while Australia recorded 14 cases between Sunday and Monday.

Both Australia and New Zealand have large tourism industries which have been heavily-impacted by the global coronavirus pandemic.

Chris Roberts, the chief executive of Tourism Industry Aotearoa, said the amount tourists spend in New Zealand had dropped by at least 2 billion New Zealand dollars ($1.22 billion) a month.

There have even been suggestions that if a corridor between Australia and New Zealand were a success, it could be a blueprint for restarting travel worldwide.

With some countries still battling coronavirus outbreaks while others are almost infection-free, links between safe destinations could provide a chance to help boost flagging tourist industries.

Australia and New Zealand have a long history of close cooperation, from trade to tourism to fighting together in two World Wars.

New Zealand even discussed becoming part of the newly-federated Australia in 1900.

Ardern said there are currently around 75,000 Australians in New Zealand and half a million New Zealanders in Australia.

"Australians and New Zealanders travel across the ditch more than they do anywhere else ... Part of the reason for so much travel is that families and friendships of course span the Tasman Sea," she said.

Travel industry experts have previously estimated that August is when the corridor is likely to be rolled out, possibly in time for the ski season in New Zealand and the school holidays in September.

Speaking at a press conference on Tuesday after the cabinet meeting, Morrison said that any announcement was still "some time away."

"But it's important to flag it, because it is part of the road back ... It is the obvious place to start," he said.