Covid-19 experts have welcomed the Government's rollout of booster vaccinations but say the drop down in alert levels for Waikato is "concerning".
Cabinet agreed to move Waikato to alert level 2 from midnight tomorrow but said the decision is a "temporary one".
Waikato has the second-highest rate of testing in the country and the area is about 3000 doses shy of reaching 90 per cent fully vaccinated.
Ardern said the decision to move Waikato to alert level 2 restrictions was based on advice from the public health team on the ground, saying it was safe to do so because cases are linked and not unexpected.
Public health professor Nick Wilson said he would have liked to see a "stronger approach" in controlling the Waikato outbreak.
"In a way the outbreak is not really under control in the Waikato we have seen spread from the Waikato to other regions," he said.
Wilson believes announcements should have been made to ensure the virus does not spread down the country.
"I think the Government hasn't really been strong enough in protecting the areas outside of Auckland to give more time for vaccination levels to increase," he said.
Wilson said the Government has been very relaxed in terms of allowing Aucklanders to cross the border.
Covid-19 Minister Chris Hipkins announced the details of the boosters programme on Monday, saying the Pfizer vaccine had already been approved as a booster in people who were 18 years or older.
Anyone aged 18 and over will be able to get a booster once six months have passed since their second dose.
Wilson was pleased to see the Government move so quickly on rolling out Covid boosters.
"The booster is likely to be very worthwhile," he said.
However, Wilson said it is important for people receiving their booster shots next April, May and June to also get the flu vaccine.
"There are growing concerns that because the Covid pandemic meant the season of influenza has been suppressed effectively quite a few people are worried that there will be a bounce-back in flu next winter."
As health workers and border works will be among the first group to receive a booster, Wilson hopes this will give them "reassurance".
"If health workers and hospitals get Covid among it's going to be reassuring for them."
National's Covid Response spokesman Chris Bishop said the announcement on boosters was overdue.
"I get daily emails from border workers, doctors, nurses and older New Zealanders who are worried about their Pfizer vaccine effectiveness waning.
"New Zealand started the vaccine rollout in February, so many frontline border workers are already beyond the six-month point for their second dose," he said.
Vaccinologist Helen Petousis-Harris also welcomed a rollout of booster vaccination shots, saying it is "completing" the course.
"What the boosters do is enhance on that second dose so you end up with a better immunity than you did at your peak after that second dose."
She said the elderly and people with compromised immune systems will benefit from a booster shot.
As boosters will be given to people six months after their second dose, Petousis-Harris said this will help those on the frontline as they were in the first group to get vaccinated earlier this year.
While questions have been raised around if Māori and Pasifika should be prioritised for booster shots, Petousis-Harris said many in these communities have only recently been vaccinated. Meaning their six months will be further down the track.
"A lot of them won't be eligible to get a booster because we didn't really go out to the wider population until June."
The Association of Salaried Medical Specialists, Executive Director Sarah Dalton said the announcement will come as a relief to many.
"It's the right thing to do. Health staff are acutely aware of the need to access boosters so it's great that they now have certainty around that".
"For health staff who work in high-risk environments it's important to know that they are being offered basic protection to keep them, their patients and their families safe," she said.