Covid-19 Response Minister Ayesha Verrall says the country needs to remain at the orange traffic light setting as case numbers are starting to "creep up".
With hospitals also under pressure from flu, a range of additional measures were being put in place over the coming months to deal with the spread of illnesses, Dr Verrall said.
Still, Covid-19 cases and hospitalisations remaining much lower than the peaks experienced earlier in the year.
"Yesterday the seven-day rolling average of Covid-19 cases was 5808 and there were 395 people in hospital and eight in ICU. For comparison when we moved out of red in April the rolling average of cases was nearly 10,000 a day and there were over 500 people in hospital including 28 in ICU," she said.
Earlier this week, the government announced the expansion of the free flu vaccine to all children aged 3 to 12 and the provision of a second Covid-19 booster for everyone over the age of 50.
She encouraged New Zealanders to get vaccinated to help relieve pressure on the health system, as unvaccinated people are over-represented in hospital admissions.
Reinfection advice amended
While reinfections are low at the moment, they would likely increase, Dr Verrall said.
"The B.5 variant of Omicron is predicted to become the dominant strain in the country in the coming weeks and is a different variant to what most New Zealanders caught the first time around."
As a result, the ministry has released updated guidelines on testing and isolation.
"We are also updating our advice around reinfection and are now asking anyone experiencing Covid-19 symptoms 29 days or longer following their initial infection to test. Should they test positive they will need to isolate for 7 days.
"This is a change from earlier advice which was that people would not need to re-test if they had tested positive for Covid-19 within the past 90 days and is based on the latest international evidence and the need to isolate quickly people with reinfections.
"However household contacts who have had Covid-19 within 90 days won't need to isolate, unless they are symptomatic."
Mask provisions at schools and ventilation
Associate Education Minister Jan Tinetti announced a supply of 10 million child-sized masks would be provided free of charge, ready for distribution at the start of Term 3.
"This means there will be 50 child size masks provided for every child in years 4 to 7 in schools and Kura throughout the country from now until the end of the 2022.
"This is in addition to the adult sized mask offered to all school children from year 8 and up. Around 20,000-30,000 masks are already being distributed to students and staff every week across the country."
Verrall said masks were very effective at reducing the spread of Covid-19 and the government wanted to support schools in encouraging their use.
"At orange we strongly recommend masks in schools and we're doing everything we can to back schools to implement that ... and we've heard from teachers that they want to be supported in the practical things they can do to encourage masks," she said.
Tinetti said more heating and ventilation funding will also be available for schools and early childhood services over winter.
"Good ventilation over winter can lead to some heat loss and higher heating bills. The winter energy payments will help reassure schools and services that they can balance heating and ventilation, without unaffordable energy bills.
"The government does not usually explicitly fund energy costs for services, but the Covid-19 pandemic is a unique situation.
"The scientific evidence is clear that good ventilation helps prevent the spread of Covid-19."
Verrall said opening windows by just 5cm was enough to help cycle the air in a school classroom, and the government's funding of heating bills would ensure that could happen.
Schools also had access to CO2 monitors - which could help identify the spaces that require good ventilation - and air cleaners, Tinetti said.
"Every school has access to more air cleaners at no cost if they need them to help supplement their approach to ventilation this winter.
"I want thank our teachers, principals and parents, who are doing a fantastic job at keeping infection rates down."