Another outbreak of measles is feared because of delays in child vaccination programmes, according to the director of the immunisation advisory centre.
Associate professor Nikki Turner said in a recent vaccinator survey, at least 50 percent reported parents weren't bringing their children in on time to be vaccinated.
There were already huge concerns internationally about childhood vaccination programmes being delayed, or poorly resourced countries missing out due to shipment problems.
"We have got really significant issues that these diseases could come back and the real killer is measles.
"Internationally, it does not take much for a childhood programme to get delayed and measles to return and we could well see there may be more deaths in our childhood population from measles than from many other issues."
She said there was a dropoff of childhood vaccinations of around 1 - 2 percent during the lockdown, and there needed to be a massive rampup of this in the coming weeks.
"We're reasonably confident that New Zealand providers are on to it now, and our outreach services are up and running," Turner said.
"[The] really strong message for us is we can't let this slip, we can't stop, we can't delay. We have to get our childhood programme going or else we're going to see problems for a whole lot of other reasons."