Health officials have announced another 36 confirmed cases of COVID-19 in New Zealand, bringing the total to 102.

Director-General of Health Dr Ashley Bloomfield made the announcement at 12:30pm on Monday.

Dr Bloomfield said half of the new cases related to travel, and most of the others are related to close contacts of people who have travelled.

"These are people who have returned to New Zealand recently and who have become symptomatic, been tested and been confirmed as having COVID-19," he said.

"Most of the remaining cases are close contacts of a previously confirmed case or are associated with an event where there were confirmed cases already."

Two cases of coronavirus in New Zealand are being treated as community transmission - one in Auckland and one in Wairarapa. Contacting tracing for all cases is ongoing, he said.

"Across all cases there are currently two where we can not be certain where the infection came from and we are therefore treating them as community transmission," Dr Bloomfield announced.

"We have expected and indeed want to find any cases of COVID-19 in New Zealand. We have expected them because we have had people returning from a range of places around the world  that have higher rates of COVID-19 and the important thing of course is that we find these cases, we isolate them, we identify close contacts and we isolate those people."

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Authorities are working to increase the capacity of Healthline, and Dr Bloomfield says the Ministry of Health has enough staff to do sufficient contact tracing.

"We have anticipated this increase in cases and in addition to the capacity that there is in all our public health units we have stood up a team here in the ministry that is able to supplement the public health units," he said.

"It can manage at the moment up to 50 new cases a day in addition to that public health unit capacity and is also scalable up as we need it."

The Prime Minister would give an update on the alert level later on this afternoon, he said. The alert level would be "a result of and informed by those cases of community transmission".

The Ministry of Health is reminding the public to get in touch with Healthline on 0800 358 5453 if they have symptoms or concerns.

What we know about coronavirus:

Coronavirus is primarily spread through droplets in the air after someone sneezes or coughs. However, it can also be contracted by touching surfaces where the illness is present, according to the World Health Organization. The length of time the virus stays alive on surfaces is unknown at this stage, but some viruses can remain active for days. 

The WHO was first informed of cases of the virus in Wuhan on December 31. It was identified as a coronavirus on January 7 and can spread through human-to-human transmission.  

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• Alert level

"Common signs of infection include respiratory symptoms, fever, cough, shortness of breath and breathing difficulties. In more severe cases, infection can cause pneumonia, severe acute respiratory syndrome, kidney failure and even death," the WHO says.

"Standard recommendations to prevent infection spread include regular hand washing, covering mouth and nose when coughing and sneezing, thoroughly cooking meat and eggs. Avoid close contact with anyone showing symptoms of respiratory illness such as coughing and sneezing."

There is currently no vaccine for the sickness.

How can I protect myself? 

• avoid touching the mouth, nose and eyes with unwashed hands
• washing your hands before eating
• carrying a hand sanitiser at all times
• being particularly mindful of touching your face after using public transport or going to the airport
• carry tissues at all times to cover the mouth and nose when coughing or sneezing (then dispose of it)
• not eating shared or communal food
• avoiding shaking hands, kissing cheeks
• regularly cleaning and sanitise commonly used surfaces and items, such as phones and keys
• avoiding close contact with people suffering from or showing symptoms of acute respiratory infection
• seeking medical attention if you feel unwell.

A full explainer on protecting yourself from coronavirus can be found here.