The government's contact tracing app has been upgraded so it can notify users about possible contact with Covid-19 cases.
Users can now choose to be notified if they have visited a venue at the same time as someone who subsequently develops the virus.
Next, they can choose to send their digital diary to contact tracers if required.
The upgrade is automatic on a person's phone unless the 'updates' function has been disabled.
Until now, the app has functioned only as a digital diary for users, and as a way for the Health Ministry to update its many outdated contacts.
A vibrate function has also been added, after concerns were raised that the app was unusable for blind people.
Three weeks after release of the Covid tracer app, 546,000 people have downloaded it, 45,100 QR Code posters have been printed out by businesses, and the app has been used to scan the posters 857,060 times.
Few businesses are displaying the app for scanning.
People have expressed confusion over the plethora of different QR Code apps developed and released during the six-week period the ministry was working on Covid Tracer, which it says took time in order to sort out privacy issues.
The World Health Organisation has urged New Zealand to further develop its contact tracing systems, in case there is another outbreak.
Local epidemiologists continue to call for tracing to be improved.
Officials have been looking for months at using Bluetooth technology for tracing, as Australia is doing.
However, they were advised recently by the Defence Force, in a paper sent from its Defence Technology Agency to the Health Ministry, that Bluetooth technology may result in false contacts or fail to record contacts that actually do occur.
Bluetooth technology relies on proximity alerts and can be more invasive than QR Code app technology.
There is also still no sign of being able to create entries manually.
Read more about the Covid-19 coronavirus:
- See all RNZ Covid-19 news
- Covid-19 symptoms: What they are and how they make you feel
- Touching your Face: Why do we do it and how to stop
- Scientific hand-washing advice to avoid infection
- Your Covid-19 questions answered - from health and employment to managing anxiety
- A timeline: How the coronavirus started, spread and stalled life in New Zealand
- Coronavirus: A glossary of terms