WELLINGTON (AFP) - New Zealand health officials cleared the way for quarantine-free flights to resume to Sydney on Sunday (May 9) as fears of a Covid-19 outbreak in New South Wales eased.

Flights were suspended on Thursday after two people in Sydney tested positive for the virus.

It was the third disruption since the quarantine-free travel bubble between New Zealand and Australia opened on April 18, almost 400 days after both closed their international borders due to the pandemic.

The earlier stoppages to flights to and from Western Australia lasted only a few days and the current travel pause with New South Wales would end at midnight on Sunday.

"The current assessment from New Zealand public health officials is that the risk to New Zealand from New South Wales remains low," the health ministry said in a statement.

"There is no evidence to suggest widespread, undetected community transmission."

New South Wales health officials said that despite extensive investigations, they had not identified how the latest cases became infected although they believe there was "contact with a currently unidentified person who was infectious in the community".

The trans-Tasman travel bubble between the largely coronavirus-free neighbours has been hailed as a major milestone in restarting a global travel industry that has been crippled by the Covid-19 pandemic.