Health New Zealand said the risk of further measles cases, contacts and exposures across the country remained "very high". (File photo) Photo: Supplied/ US CDC
Two more cases of measles have been confirmed, bringing the total outbreak number in Aotearoa to 13.
Dr Nick Chamberlain from Health NZ told media 2142 close contacts had been identified so far.
Health authorities said contact tracing for measles was under pressure in the Wellington region.
Seven cases had been linked to a Bluebridge Ferry crossing on October 3.
Health NZ said it was "pretty pressed" though not short of tracers in the central region.
The outbreak was in its early stages when contact tracing was "incredibly effective".
The new tracing technology system called the NDMS was proving "incredibly helpful", Chamberlain said.
"It does reduce hugely the amount of manual activity" and could be used for bulk texting and divvying up cases around the country, he said.
A test took place in May of contact tracing in a simulated surge, Cabinet papers released by the ministry showed.
"It passed," Chamberlain said.
Contact tracing systems had to be stood up rapidly in often jerry-rigged fashion among the fragmented public health units during Covid-19.
The Cabinet papers said the tracking system remained "untested" for effectiveness in a major or multiple outbreak.
In addition, even good contact tracing has limited effectiveness on measles "beyond the early stages of an outbreak" because the virus is so infectious.
But this was still in the early stages, the ministry said on Thursday.
The papers showed no shift towards giving government support to exposed people asked to quarantine for two weeks, off work and sometimes not even able to live at home, such as if there are babies there.
Work on this was done last year then dropped.
"Cases and contacts (or their caregivers) that are required to isolate or quarantine must take leave (paid or unpaid) and rely on the support of friends and whānau," said a Health Ministry briefing to Minister Simeon Brown in May this year.
Chamberlain said support such as care packages and even up to financial support could be offered in the latest cases of people exposed who had to isolate. That would be done through the contact tracing or other teams.
A local expert review of measles preparedness last year recommended ensuring adequate support.
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