COVID-19: Source of cases

What we know about how COVID-19 has spread since the virus arrived in New Zealand.

Last updated 1pm 30 November 2020.

All data on this page is as at 9:00 am on 30 November 2020 unless otherwise stated.

Data is collected from the EpiSurv database (administered by ESR), unless otherwise stated. This page is updated as new information is available.

On this page:


How COVID-19 has spread in New Zealand

When new cases are reported, isolated and investigated, we learn more about how COVID-19 has spread.

When clusters emerge, moving to Alert Levels 3 and 4 has slowed the spread of the disease.

Each person within a cluster with a confirmed or probable case of COVID-19 is asked:

  • if they recently travelled overseas
  • who they've spent time with
  • where they've been (eg, shops, medical centres).

Health professionals and scientists can use this information to stop further transmission by:

  • finding out how each person may have caught the disease
  • monitoring how the disease is spreading.

If COVID-19 was spreading rapidly, investigating every case would be more difficult for our health system. 

How COVID-19 has spread
  Number of cases Percentage (%) of all NZ cases
Imported case 1 918 45%
Import-related case 2 478 23%
Locally acquired, linked 3 571 28%
Locally acquired, unknown source 4 89 4%
Under investigation 0 0%
Total 2056 100%
  1. International passengers and crew entering the country who caught COVID-19 overseas or during the journey
  2. People exposed to international returnees - includes close contacts, other returnees in managed isolation or quarantine, and staff working at the border or in managed facilities
  3. Caught COVID-19 from someone locally
  4. Caught COVID-19 within NZ (hadn't travelled overseas recently or been in close contact with someone who travelled recently) but source is unknown

Daily confirmed and probable cases by source

Transmission type of COVID-19 cases
Daily confirmed and probable cases by source
COVID-19 cases by source and ethnicity
  Māori Pacific peoples Asian Middle Eastern/Latin American/African European/Other Unknown
Import-related case 67 12 45 12 341 1
Imported case 42 17 189 36 626 8
Locally acquired case, unknown source 9 7 13 3 57 0
Locally acquired, epidemiologically linked 72 148 116 17 218 0

Monitoring spread within clusters of cases

Clusters of cases are groups of ten or more people who likely caught the disease from one another.

Clusters generally start where people are together in one place. Examples include:

  • a holiday or a special event (on a cruise ship, at a conference, attending weddings)
  • in their community
  • at care homes for the elderly
  • at a school.

Clusters are investigated and managed by public health officials. This includes confirmed and probable cases.

Public health staff quickly:

  • follow up any cases of COVID-19
  • find out who the person was with recently (close contacts)
  • ask close contacts to isolate as well.

This action contains the clusters and prevents the disease spreading any further.


Cluster details

Cluster under investigation Location Total to date New cases in last 24 hours Current active cases Origin Status*
International Mariners Christchurch 33 0 0 Overseas exposure Open
Auckland August Cluster Auckland 179 0 0 Under investigation Closed
Aged Residential Care Facility (2) Auckland 13 0 0 Overseas exposure Closed
Aged Residential Care Facility (1) Auckland 51 0 0 Unknown Closed
Aged Residential Care Facility (1) Christchurch 56 0 0 Unknown Closed
Aged Residential Care Facility (2) Christchurch 19 0 0 Unknown Closed
Private Function Auckland 40 0 0 Unknown Closed
Group travel to USA Auckland 16 0 0 Overseas exposure Closed
Ruby Princess Cruise Ship Cluster Hawke's Bay 25 0 0 Overseas exposure Closed
Community Auckland 30 0 0 Unknown Closed
Hospitality Venue Matamata 77 0 0 Overseas exposure Closed
Wedding Bluff 98 0 0 Overseas exposure Closed
Community Christchurch 14 0 0 Overseas exposure Closed
Marist College Auckland 96 0 0 Unknown Closed
World Hereford Conference Queenstown 39 0 0 Overseas exposure Closed
Aged Residential Care Facility Waikato 15 0 0 Overseas exposure Closed
Group Travel to USA Wellington 16 0 0 Overseas exposure Closed
Wedding Wellington 13 0 0 Overseas exposure Closed

* A cluster of cases is considered closed if there are no new cases for 28 days after the people involved completed their time in isolation (28 days is twice the length of the incubation period of COVID-19).

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