New Zealanders coming back to New Zealand from China would be allowed to come home, but would need a quarantine period of 14 days.
The prime minister is giving an update on the Government's response to coronavirus.
Ardern said the Government was still looking at an exemption for Chinese tertiary students coming to New Zealand to resume their studies, but it would need to be practical and allow such people to self-isolate for 14 days after arriving.
New Zealand had the same public safety measures in place that already existed in Australia, she said.
She said critical clinical equipment was available such as anti-virals and masks, including nine million P2 masks and nine million general surgical masks ready to be used in the case of a pandemic.
"We have access to negative pressure rooms across 15 DHBs," she said, which would prevent cross-contamination from room to room.
A quarantine facility could host 150 people from Wuhan, where the virus was first found, she said.
These preparations would put New Zealand in a better place if and when coronavirus found its way to New Zealand.
"We are ready from a public health perspective."
Finance Minister Grant Robertson, who appeared alongside Ardern this afternoon, said that an economic advisory group was taking an in-depth look at the impact of coronavirus on the New Zealand economy.
He said the IMF had revised down its global growth forecast, though it is still expected to return to normal in the second quarter of the year.
The New Zealand economy would see a significant hit in the first half of this year, Robertson said, but would stabilise in the second half of the year.
The Ministry of Social Development was already "on the ground" to support the logging sector, helping them to find other jobs, he said.
The group was also assessing scenarios where there was a long-lasting shock to the economy, or a global recession.
Robertson said the economy was in a strong position to absorb the potential impacts of coronavirus.
"We are planning for these scenarios but we are not predicting them."
He said he would meet the tourism sector along with Tourism Minister Kelvin Davis tomorrow evening. That was in addition to the $11m fund that was announced last week.
Forestry workers that were struggling were being directed to other potential jobs including track maintenance for the Department of Conservation, he said.
This morning Ardern said she expected to travel ban on foreign nationals coming to New Zealand from mainland China was likely to continue, but there had been no discussions about excluding travel from countries other than China.
"No one here is proposing that we put in place a travel ban that basically starts picking up Europe and the like," Ardern told Newstalk ZB's Mike Hosking this morning.
Major outbreaks have forced Italy and Iran to introduce internal travel restrictions, while South Korea's president Moon Jae-in placed the country on "red alert" after the total number of confirmed cases hit 556.
The Australian government has extended its ban on foreign nationals arriving from China to Saturday, but is allowing some high school pupils from China to enter on a case-by-case basis.
Universities NZ has asked the Government for an exemption for foreign students stuck in China, and Ardern said the Government was still considering this.
But she appeared to hint that an exemption would be unlikely.
"There's no point doing this unless we can guarantee people would be quarantined properly," she said this morning.
Asked if an exemption would be too difficult, she said: "I don't want to say that yet. We are really properly teasing it out. We owe it to the sector to do that."
Last week the Chinese Ambassador to New Zealand Wu Xi has questioned why the ban was imposed against the advice of the World Health Organisation.
Ardern has announced an $11 million package to help the fallout from coronavirus that has hit the tourism sector.
She said at the time that the Government was still considering what it could for other sectors, such as affected businesses and forestry.