One of the children managed to unlock a fire-exit gate after climbing on top of a trike.
The girls travelled 320m, from the centre near the intersection with Ford Rd, across the intersection at Kusabs Rd, to the intersection at Edmund Rd and up to outside 5 Edmund Rd.
They were seen near the centre by a member of the public driving past. By the time driver pulled the car over and alerted the centre, about three minutes had passed.
About the same time staff realised the three girls were missing and fetched them back.
Casey said there were 104 licensed early learning centres within the Rotorua district with an additional six licensed home-based services.
"Early childhood education services must always have a certain number of adults for the number of children attending. This is called the adult-to-child ratio. Both the adult-to-child ratio and number of qualified staff have to be kept at all times.
"This includes when the service takes children on an excursion or when adults go on lunch or other entitled breaks."
The adult-to-child ratios in an education and care centre is split into two categories.
For under 2-year-olds the ratio is one adult for every five children.
For children 2 and over the ratio is one adult for the first six children. After that the ratio is one adult for every 10 children.
At the time of the incident ABC Sunset was meeting the minimum requirements.
Fiona Hughes, the deputy chief executive of BestStart Educare, which runs the ABC centres, told the Rotorua Daily Post the centre received "quite a lot" of support after the incident was reported. "The parents have been very considerate and understanding. The centre was buzzing this morning with parents coming in to offer their support," she said.
"The staff are upset that this has happened, and we do have a good relationship with the parents, so it's nice to see they have rallied around."