School principals are welcoming confirmation that all students can return to schools and childcare when the country moves down to alert level 2.

Prime Minister Jacinda Ardern has confirmed parents will no longer be encouraged to keep children at home if they can, as they were during the level 4 lockdown and under level 3 restrictions since last week.

Classes will resume for senior high school students in Years 11 to 13, who all had to stay home in level 3, and tertiary education institutions will reopen.

However, online and other forms of distance education will still be available for children who need to stay home due to health conditions.

Ardern said schools would not open mid-week even if level 2 was adopted for other sectors two days after a Cabinet decision, possibly this coming Monday.

"When the decision is made, they will open at the beginning of the following week," she said.

That means the earliest schools and early learning centres might be opened to everyone is Monday, May 18.

Ardern said the official advice remains to keep students 1 metre apart indoors and 2 metres apart outside, but she accepted that this would not always be practical.

"We do, however, know that it's near-impossible in the early learning environment, and very challenging in schools, so staying home if you're sick, hygiene protocols and regular cleaning become even more important," she said.

Principals' Federation president Perry Rush said principals welcomed the news and were "keen to get back in front of our young people".

• Rules around level 2 to be decided today; could take effect from next Wednesday
• What will life look like under alert level 2? Rules and restrictions revealed

"We think it's really important that every student gets back to school at this time," he said.

"We would think that the measures regarding social distancing will be considerably relaxed. That is appropriate in regards to early learning, and I think the Prime Minister also made a strong statement around the safety of schooling."

Auckland Grammar School headmaster Tim O'Connor said he was still waiting to see the statistical data that justifies reopening schools from a public health perspective, and details from the Ministry of Education around physical distancing.

"I expect there will be an expectation that we do meet our 1 metre social distancing wherever possible," he said.

"That is what we have been preparing for. We have been retimetabling the entire school to be able to do that. We wouldn't have all cohorts on site, we'd be rostering them on site and having a mix of on-campus and online learning.

"But if there is no public health requirement for social distancing, that makes it pretty easy - we're back and we're operating."

Post Primary Teachers Association president Jack Boyle said schools would need to have "conversations" with any teachers who feel vulnerable because of age or health conditions.

But he said there would not necessarily be an expectation that vulnerable teachers should stay at home this time, even though they were told to stay home when the country moved to level 2 on March 21 when the virus was uncontained in the community.

"If the public health advice is that the likelihood of transmission with schools open at alert level 2 is not that there will be increased risk, then I guess that would include those workers who previously at alert level 2 and 3 as we went up were in a different context and there was more risk," he said.

Early Childhood Council chief executive Peter Reynolds said he was waiting to see detailed advice on issues such as whether childcare centres should still keep children in separate "bubbles" and whether they still needed to have 3 square metres of indoor space per child, up from 2.5 square metres before the lockdown.

"On the advice of public health officials, any educational facilities connected to a confirmed or probable case of Covid-19 must close on an individual or group basis to allow contact tracing, and then potentially for a further 14 days," the Government's Covid-19 website says.

"Early learning services and schools are safe environments for children, young people and staff. Additional public health control measures are in place to prevent the spread of disease and to support contact tracing," the website says.

"Tertiary education is a safe environment for students and staff to return to at alert level 2.

"Tertiary education facilities will implement public health requirements and physical distancing as appropriate for the context and will work closely to ensure a safe environment where students can continue their learning. They will need to maintain distance learning capability to help manage within these constraints, and ensure the safety of staff and students at risk of Covid-19.

"Workplace-based learning will be conducted within the specific rules applicable to the relevant industry."

The announcement has fleshed out the high-level statement in the original chart of the four alert levels that schools and early learning centres "are open for all children" at level 2.

"Distance learning is available for those unable to attend school (e.g. self-isolating)," the chart said.

"Tertiary education facilities open, with arrangements made for vulnerable students
for distance learning.

"Any educational facilities connected to a confirmed or probable case of Covid-19 must close on an individual or group basis for 72 hours to allow contact tracing, and then potentially for a further 14 days."