Prime Minister Jacinda Ardern says travel restrictions won't be extended to South Korea and Italy, but advice may be given to people in specific regions to self-isolate if they travel here.

She will bring the issue up at today's Cabinet meeting which is expected to be dominated with discussions about New Zealand's preparedness for more cases of Covid-19.

The government announced on Friday travel restrictions would be extended to Iran, after a man who'd travelled through there was diagnosed with the virus in Auckland.

Today, she told Morning Report there's very clear criteria for why the travel restrictions are for China and Iran only.

"The vast majority of cases are still coming out of there," she says.

There are also hotspot areas, such as Seoul in South Korea and northern Italy, but she says it's not possible to differentiate if someone has been in a particular region, rather than country.

"What we'll be considering today and talking about at Cabinet, and we've really been pushing health officials on this, is whether we should have specific advice for people in those regions to self-isolate.

"The advice to date has been from health officials, but we're really leaning on them on this one because we think there might be more we can be doing."

She says that with specific advise, people looking at travelling to New Zealand from hotspots in South Korea and Italy might reconsider their plans.

Jacinda says our health system has been at a heightened state for some time now.

"Our pandemic plan always sits at the ready, but we've really operationalised in response to Covid-19 at the beginning of January."

She says that while it's a significant event for New Zealand, and the world, we do need to remain calm.

"We need to add that layer of reassurance that this is the kind of situation that New Zealand is well prepared for and that we have an excellent health system."

"SARS was an eight-month period many will have forgotten which New Zealand, like others, was having to address and the memory of that still sits with our public health officials and informs our pandemic plans."

"I would also point out that other countries experiencing cases have contained and managed to stop wider community outbreak. That is the focus for New Zealand, and we've done very well to date."

RNZ.