From 1 January 2019 to 9 September 2019 there have been 1131 confirmed cases of measles notified across New Zealand - 944 of these confirmed cases are in the Auckland region.
Prime Minister Jacinda Ardern said the New Zealand government is continuing to give very strong advice to everyone to get immunised.
"We're working on making sure access to immunisation, particularly in South Auckland is readily available. We've deployed additional nurses into public places like churches, and those areas where people might generally frequent to make it easier for them to access immunisation."
Ms Ardern said New Zealand is not the only country facing a measles outbreak, noting a 300 percent increase globally on last year of measles cases.
New Zealand health authorities are advising people between the ages of 15 and 29 to check their immunisation records making sure they've had two doses of the MMR vaccine as a child and if not to get a free booster shot.
Auckland Regional Public Health's Dr William Rainger said in Auckland approximately 25 percent of measles cases have identified as Māori, over 45 percent as Pacific, 25 percent as Pakeha and around five percent as Asian or other.
He said most Pasifika cases have been in the Samoan and Tongan communities.
The World Health Organisation's communicable diseases expert for the Pacific Dr Angela Merianos said the wider region was warned about measles months ago.
The WHO and UNICEF wrote to all the Ministers of Health in the Pacific five months ago detailing both prevention guidelines and proper outbreak response.
"We sent the letter back on 9 April actually alerting them to the re-emergence of measles globally and, in particular, the emergence of measles and measles outbreaks in a number of countries of the Western Pacific and South East Asian regions. Given the degree of travel that occurs between these countries and the Pacific."
Dr Merianos said people going to Auckland must be aware of their immunisation status.
She said people aged under 50 with no medical contraindication to vaccination should get two doses of vaccine well ahead of travel to any of the outbreak areas.
"Because every vaccine takes about a week before the immune system can respond to the vaccine and provide protection. So, it is important that people plan ahead and make sure that they're vaccinated before travel," Dr Merianos said.
In the Cook Islands hospitals are preparing isolation beds and notices are going up at the airport as New Zealand's measles outbreak threatens infants and tourism numbers.
Health Secretary Dr Josephine Herman said extra vaccine supplies have been ordered as authorities bring down the age of immunisation from 15 months to 12 months.
She said it's possible tourists from New Zealand coming to the Cook Islands may not know they have the illness.
"We are quite concerned now. We have about 21 flights coming in from Auckland every week. And we have quite a solid tourism industry which we would like to protect. But the main concern we have is for our babies that are 12 months or younger."
Dr Herman said all arriving passengers will be given information at the airport telling them what to do if they become unwell while they are in the Cook Islands.
She estimated vaccination coverage at 90 percent.
"Our population moves quite frequently between the Cook Islands and New Zealand. About 30 percent of our babies are living in the pa enua, the outer islands, so we are thinking we are sitting at about 90 percent.
"We are in the process of establishing an electronic register which makes it easier for us to collect this data."
Dr Herman said they are working hard to prevent Cook Island babies from being exposed to the virus by visitors from New Zealand.
Fiji has issued a public health warnings and travel advisories, offering free MMR vaccinations and asking people to get immunised two weeks before visiting New Zealand if they are not already protected.
The last outbreak in Fiji was in 2006, and there have been no cases since then and their Health Ministry is warning people to be alert for fever, coughing, sore eyes and a rash.
The Fiji Health Ministry warned some people infected with measles may develop severe complications such as pneumonia or encephalitis requiring hospitalisation.
Young children, pregnant women and those with compromised immune systems are at higher risk of measles complications.
The Director General of Health in Samoa, Dr Take Naseri, is asking anyone with measles symptoms not to fly as numbers surge to over a thousand cases in New Zealand.
RNZ Pacific's correspondent Autangavaia Tipi Autangavaia said Dr Naseri confirmed there is no measles in Samoa, at a press conference last week.
"The immunisation programme is now being carried out since April. And so far, Samoa is clear of any outbreak of measles. But the Ministry of Health he said is still on alert. And doing their check up at the airport for passengers coming in and for those who are leaving the country."
He said there is no panic about measles in Samoa and the public appears to be travelling as normal.
Dr Naseri said reluctant parents have had time to discuss their hesitations about immunisation but pointed out parents who outright refuse to vaccinate are also quick to seek treatment from the hospital when their children get sick.
Last month the Nurses' Association said Samoa's health system has improved since the deaths of two infants last year caused by human error not vaccines.
Clinicians from New Zealand travelled to Samoa in June, training nurses at hospitals on both Upolu and Savai'i and many children were immunised in a catch-up programme.
The WHO's Dr Merianos said in addition to full immunisation for those under 50 years old, the WHO has protocols on identifying measles, clinical treatment, infection control and isolation.
She said measles is very contagious with each case able to infect up to 12 others with the airborne virus lingering for about an hour in enclosed spaces.
Measles can easily spread in clinic waiting rooms infecting other patients who are vulnerable and exposing medical staff too.
"So, we want people to be aware and to ring ahead. And when they are diagnosed with measles, to follow recommendations for their isolation and they should remain isolated for at least five days after the rash appears and they become symptomatic."
Dr Merianos said it can take about two weeks for people to get sick with measles after first being exposed to the virus.
Pacific travellers to and from Auckland were first warned to vaccinate against measles at the end of August.
New Zealand's Director of Public Health said a lot of people have close ties with the Pacific region and with school holidays approaching at the end of September, many people are planning to travel.
UNICEF works with the WHO to deliver vaccination programmes in the region and its Pacific head Sheldon Yett says measles is one of the most contagious diseases known, meaning it's vital travellers to the Pacific are immunised.
"The irony of course is that we usually caution people not to get sick when they go to Pacific Island countries. Make sure they take basic public health precautions. But of course, in this case it happens to be true for people going to Auckland if they're not vaccinated.
"We know that contagion is just a plane ride away. It's very easy for someone to get on a plane, not know that they're sick and get sick a couple of days later. And expose people in the airport, expose people in the flight around them and expose many other people to the disease.
"So, air travel makes proximity so easy and travel so easy it does put populations at risk, no doubt about it."
He said it is absolutely essential all Pacific parents protect their children.
"We know that children are ten thousand times more likely to be brain damaged by the disease than brain damaged by a measles vaccination. Vaccine is very safe.
"We know it's safe. It's tested around the world, it's used around the world, we know it's safe, it's one of the safest things and one of the best things you can do for your child."
Sheldon Yett said Unicef and WHO are doing a lot to boost immunisation rates to achieve herd immunity in the Pacific and vaccines are in good supply in the region.
The WHO's Dr Merianos said health workers are skilled at having conversations with parents about vaccine safety and immunisation is one of the most cost effective public health measures and has literally saved millions of lives.