The Prime Minister is considering further travel restrictions from coronavirus "hotspots", as the Government travel ban widens.
Jacinda Ardern told Newstalk ZB's Mike Hosking that the announcement to shut down the border to Iran came just before the first New Zealand case was confirmed.
"We did know we had a potential case, but at that point there were still negative tests coming through."
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The Prime Minister said travel to countries with a high number of cases - such as Italy and South Korea - was still open at this stage, but would be monitored as the level of infection was still unknown.
"We make judgements based on scale - whether or not we believe we've got a true sense of transmission - the health system in place, the border controls and border measures that are being in used, both within in the country and in transit to New Zealand."
Ardern said the public should follow basic hygiene practises, and the Government would be closely monitoring whether more-specific measures were necessary.
"[There] might not be a reason for a complete ban for travel from those countries, but what about being regionally specific and saying 'if you have come from that region, self isolate'?"
The Government announced a travel ban from people travelling from mainland China since February 2.
The first New Zealand Covid-19 case was announced on Friday, sparking panic buying of emergency items at supermarkets with reported queues running out the door.
On Saturday, Ardern called out the media on their coronavirus reporting and said she took particular exception to the headlines.
"I do appreciate that not all journalists write their own headlines, but now is the time for factual information and giving the public as much factual information as possible.
"Those headlines did a disservice to the media in New Zealand and also the public."
There is one patient being treated for coronavirus at Auckland Hospital, and 11 Covid-19 tests currently awaiting results.