Less than half of the children enrolled in daycare centres around Auckland have been able to go back today, leaving many parents disappointed, according to the Early Childhood Council.

Phase One of Auckland's move out of level 3 restrictions was announced by Prime Minister Jacinda Ardern at 4pm on Monday and kicked in today. One of the changes meant early learning services were now open to more children.

However, Early Childhood Council interim chief executive Sue Kurtovich said demand had been high from parents eager to no longer juggle work and looking after children at home after 50 days of level 3 and 4.

She said the biggest issue was raising parent expectations around being able to access a space when the reality was those spaces were unlikely to be there in many services.

Kurtovich estimated less than half of enrolled children would be able to return to their daycares because many only attended part-time.

"It was very simplistic to imagine that you could simply say Early Childhood Centres were open for all and announce that from the podium without any reference to what the supply was going to be or even talking to the sector and giving them the rules beforehand.

"It was actually gobsmacking. We were just blindsided."

Kurtovich said it was not until 4.30pm last night that centres received a bulletin from the Ministry of Education clearly outlining the requirements.

Under normal level 3 restrictions centres were only allowed to open to care for children whose parents needed to leave home to work and where no other childcare options were available.

From today, early learning services were available to all children but centres had to be able to maintain separate bubbles of no more than 10 children. The Ministry confirmed last night that bubbles included children who were only there part-time.

In the bulletin sent last night and signed by secretary of education Iona Holsted, the Ministry acknowledged not all children would be able to return and suggested centres continue to prioritise families whose parents had to leave home for work.

Given little time to figure that out, Kurtovich asked parents to bear with their early childhood provider for the time being.

"We absolutely cannot meet the demand of absolutely every parent who will want early childhood education in Auckland and there will need to be a priority system and it does seem to have been left to the centres to determine their own priority system," she said.

"It's not just a simple matter of saying we're licensed for 40 children, we can have two bubbles of 10 so we can have 20. A centre license for 40 could have 80 children on the role because you have lots of part-time children but you're still only going to be able to take 20 because they have to be exclusive bubbles.

"You can't have Johnny coming Monday, Wednesday, Friday taking a space and Sally coming Tuesday and Thursday. It just doesn't work that way."

The Ministry's advice also stated centres needed to have 3 square metres of indoor space for each child in the bubble of 10 - a slight increase on the usual 2.5 square metre requirement.

That requirement had not been brought up as an issue because the bubble rule meant most centres were already running below capacity, Kurtovich said.

The bulletin also said testing for teachers was not mandatory but suggested they should get two Covid tests in the next two weeks as a precaution.

She said the most disappointing thing was that it didn't need to be a last-minute scramble for owners and managers.

"We could have been included in the discussions, we could have explained the challenges, we could have sorted out how much supply we had. We could have provided advice around that," she said.

"It's been hectic and it's been busy and, for me, the frustration is that all of that could have been avoided had somebody just spoken to the sector before."