The Prime Minister has warned New Zealanders to keep following physical distancing guidelines even if they wear masks, saying face coverings are "not a replacement" for social distancing.
Auckland is moving to "alert level 2.5" - as Jacinda Ardern described it - at 11:59pm on Sunday. The rest of New Zealand will remain at level 2.
Furthermore, from Monday, anyone who takes public transport must wear a mask or face covering for their journey if they're aged 12 or over. This applies to buses, trains and ferries, as well as taxi companies and rideshare apps.
Ardern also encouraged Kiwis to wear a mask whenever they leave the house, but warned this shouldn't be the only public health guideline they follow.
"Keep in mind, at level 2, social distancing is required. So social distancing in retail, social distancing in hospitality are all built into the rules," she said during a press conference on Sunday.
"Mask use is not a replacement for social distancing - it must be in addition to. This is something that health officials have been very clear on, so I wouldn't want anyone to think that if you've got a mask, you can then be in close proximity to strangers. We're asking for both."
Since masks will be compulsory on public transport from Monday, Ardern said there is a "very clear expectation" people must wear them, but education and support will be provided in the early stages of enforcement for those who don't have a face covering.
"We will be mindful and we've worked alongside transport providers to make sure that in these early stages we're working to support people around masks and face coverings. They have options available to them that if people have nothing, they can support people so that we don't have people stranded as a result of not having masks and face coverings."
While it isn't compulsory that masks are worn all the time when people leave their homes, Ardern said it hasn't been ruled out and will be enforced if Cabinet believes it's necessary.
"It's not a simple thing to ask to suddenly mandate and create a legal framework around that. We are going as far as we can though and saying we are strongly encouraging their use, and as a Cabinet we will reserve the right to mandate if we believe that it's not being appropriately used, particularly in Auckland where we're really encouraging that use," she said.
"There are a range of issues you have to become really mindful of [when creating a mandate]; how do you make sure you're enforcing it, what's the penalty regime, who is responsible for enforcing. For instance, would you require retailers to bar people from entering a shop if they're not wearing a mask. You then have to think about what happens in cases of escalation."
Director of Public Health Dr Caroline McElnay said the Ministry of Health's advice was focussed on what should be mandated in New Zealand's current COVID-19 environment.
"In an alert level 2 environment, which is low levels of community transmission, we considered that the highest risk was in a public transport situation environment, and that therefore there would be merit in mandating mask-use in that environment," she said on Sunday.
"But that's a different situation to generally encouraging mask-wearing in addition to all the other public health interventions that are available."
Alert level 2 and '2.5' restrictions will remain in place until at least September 6.