New Zealand health officials will place Wellington on Alert Level 2 Wednesday, after an Australian man infected with the Delta strain of Covid-19 spent two-and-a-half days touring the capital city before returning home to Sydney and testing positive, Bloomberg reported.

"This is not a lockdown...these are precautionary measures which will remain in place while we contact-trace and test all of those we need to," response minister Chris Hipkins said during a news conference in Wellington.

Hipkins said the man had been administered with one dose of the AstraZeneca vaccine and the person who he traveled with is awaiting her test results, the report said.

According to Hipkins, the government would consider a further tightening of restrictions if infections start to emerge in the community outside the groups identified through contact tracing.

"Even though we have no positive cases at the moment, we do know we had a positive case and that person had some extensive, potential exposure in the Wellington region," Hipkins said.

Under Alert Level 2, businesses, schools and offices can remain open but must maintain safe distancing and observe other pandemic rules.

Recreation and sporting activities are allowed, subject to conditions including physical distancing, but gathering of more than 100 people are restricted, including at funerals, weddings and other social events.

With 5 million people, New Zealand is one of the handful of nations that have contained the spread of the virus and returned to normalcy. It reported its last positive case from a community transmission about four months ago.

New Zealand is vulnerable to an outbreak because its vaccine distribution has been slow. Vaccination of the general population is set to begin at the end of July, Bloomberg said.

Meanwhile, New South Wales Wednesday tightened restrictions on public gatherings and movement of people in Sydney for one week in the wake of fears the latest Delta variant cluster could spark a major outbreak.