Jacinda Ardern defends meningococcal response after 3 deaths

The Prime Minister is defending a DHB's decision to keep rising meningococcal levels a secret.

An in-house Northland DHB memo reveals staff were warned to vaccinate their kids six months ago but it didn't properly warn the public about the deadly disease until early this month.

Appearing on The AM Show on Tuesday, Prime Minister Jacinda Ardern says she'll be asking questions about this.

"On the face of that you would think that would be a trigger point at least for them to be talking to the Ministry of Health, absolutely," she says. "But I can't rule out that that didn't happen."

Ms Ardern says that since the outbreak has been declared there's been "very very quick action".

"I can't comment on the timeline from within Northland DHB. What I know is it's only been very very recently that it's been declared by the experts to be at outbreak level," she told host Duncan Garner.

"We've got 29 cases, and three deaths - and that's now reached the level particularly in Northland they can make that declaration."

On Monday, Health Minister Dr David Clark announced that from December children and teenagers in Northland would be vaccinated to deal with a dangerous meningococcal outbreak.

Vaccines are being flown in from overseas, and the first batch of 10,000 doses - covering the A, C, W and Y strains - will arrive in New Zealand next week. Another 10,000 will follow a few weeks later.

The three-week programme will include free vaccinations for children between nine months and four years of age, as well as teenagers. Immunisation clinics will be set up in selected high schools and community centres across Northland.

Ms Ardern says 20,000 vaccines have been bought and the most vulnerable will be targeted first.

"We're acting in the region we're seeing the most cases, we're asking people still to be vigilant around the symptoms they might see and we're trying to target as many as we can who are at the most risk," she says.

"Right now our priority is making sure we're getting as much information out there to parents that we can, in particular that we get that vaccine programme underway and we do what we can to protect that population particularly in Northland."