The prime minister is announcing Cabinet's decision on possible changes to alert levels for Auckland, Northland and parts of Waikato.
Covid 19 Response Minister Chris Hipkins and the Director-General of Health Dr Ashley Bloomfield will also be part of the live-streamed briefing.
The government will announce a new Covid-19 protection framework on Friday for when the country is at a higher vaccination rate.
On Wednesday, Hipkins will provide up-to-date advice on schools reopening.
"We know that, in the future, we cannot ask people to live week by week not knowing when things will change," Ardern says.
Ardern says it appears the people who travelled in Northland have not spread Covid-19 further.
Northland will move to level 2 at 11.59pm on 19 October.
For Waikato, "the situation is different".
"While the cases remain broadly linked, this linking is often occurring after the positive results are being returned."
She says there is a need to act with caution in the Waikato after positive cases and wastewater testing came back positive.
Waikato will be held at level 3, to be reviewed on Friday.
For Auckland, Ardern acknowledges its been a long time to be living with restrictions
"But those restrictions have made a huge difference, they've helped us to keep case numbers as low as possible while we continue to vaccinate people.
"We need to keep going with both tools: our restrictions and vaccinations, because with Delta we cannot rely on just one.
"If we get this right, if we keep case numbers low while we vaccinate people, then it makes it easier for us to keep control of Covid while we ease restrictions in the future."
Auckland will remain in level 3 with current restrictions for another two weeks.
She says the alert level 3 rules in Auckland are the toughest restrictions in place anywhere in the OECD at the moment.
Ardern acknowledged experts suggesting a level 4 circuit breaker for Auckland but says public health advises it would be unlikely to reduce case numbers "because of the nature of the outbreak and compliance has been an issue".
She says any easing of restrictions over this time will not work towards the plan of minimising cases will vaccination rates increase.
There are now Covid-19 cases across 124 suburbs of Auckland.
On staying at level 3: "I know this is hard and I want to acknowledge the ongoing impact on Auckland businesses of staying at level 3."
She says an enhanced business support package for Auckland is being worked on, which will be revealed on Friday.
The rest of New Zealand will remain at level 2.
There were 60 new community cases of Covid-19 announced today - 57 in Auckland and three in Waikato.
RNZ understands ministers were also due to consider a traffic light-like system New Zealand could move to once the population is highly vaccinated.
It could mark the next phase, away from using alert level restrictions, to a mix of protective measures in the event of outbreaks.
That could include mask use, gathering limits, social distancing, proof of vaccination and scanning.
It could be some months before it would be ready to be implemented.
The government's repeatedly said high vaccination and testing rates will help towards easing restrictions.
National leader Judith Collins said that Ardern "must today tell the country the conditions and timeframe for ending the lockdown in Auckland and then she needs to get up there and see for herself the fallout from nine weeks of lockdown".
If it was true restrictions in Auckland wouldn't be eased until there was 90 percent double vaccination, which could take another month, the prime minister "must say so today and give Aucklanders and the rest of the country some certainty", she said.