Kiwi kids who go to early childhood education centres tend to make friends easier but are also likely to get sick more often, new research has found.

Exactly what effects early childhood learning has on a child's emotional development and wellbeing have long been debated by academics and parents alike.

That made the new Auckland University of Technology and University of Auckland research an important addition, author and associate professor Andrew Gibbons said.

Its findings were based on comments parents made about their child's behaviour and illnesses as part of the Growing Up in New Zealand study, which is following the lives of 6000 Kiwi kids born in 2009-2010.

The research found parents, who sent children to an early learning centre, viewed their child's behaviour at 4-and-a-half years of age "more positively" than parents whose children didn't.

Early learning centre kids also tended to have "better relations with their peers", according to the parents' reports.

"These findings suggest that early childhood services may contribute positively to the complex task of supporting young children's healthy relationships with themselves and their peers," AUT's Gibbons said.

However, while the new New Zealand findings were welcome - given most earlier studies on the topic had been undertaken overseas - it also highlighted the need for further research.

"It's important to further understand the effects of different types of early childhood education, teacher-child ratios and license size, teacher qualifications and working conditions," Gibbons said.

And while the research highlighted how early learning could be good for a child's emotional wellbeing, it also showed there were potential nasty side-effects due to increased risk to infectious illnesses.

For example, 9-month-olds going to childcare centres had twice the risk of ear and chest infections compared with infants cared for primarily by a single carer.

They were also 2.5 times more likely to have gastroenteritis than infants cared for by their parents.

Two-year-olds attending childcare centres, meanwhile, had 2.2 times greater risk of ear infection, 1.8 times greater risk of chest infection and 1.5 times risk of gastro infections.

For infants spending more than 30 hours a week in care, this increased risk could also result in more serious conditions.

"There is evidence that infections in early childhood can provide immunity against illnesses later on," fellow research author from the University of Auckland Dr Sarah Gerritsen said.

"However, some of the infections we saw in the Growing Up cohort were serious. For instance, one in eight preschoolers attending childcare had been admitted to hospital with a chest, ear or gastro infection."

The research was undertaken before the recent global outbreak of Covid-19.

That meant early learning centres would likely have developed new protocols and increased vigilance around infection control, Gerritsen said.

"But it is a good reminder of the need for public health agencies to work closely with the early learning sector to reduce the spread of infections," she said.

She also reassured alarmed parents that there had been no Covid-19 cases in New Zealand spread at early childhood services.

"And an Australian study showed that the risk of children and staff transmitting the virus in schools and early childhood education settings is very low given the contact tracing and epidemic management system in place," Gerritsen said.

HOW THE FINDINGS COULD IMPACT GOVERNMENT POLICY

• Centre-based care at 2 years of age may have benefits for children's emotional wellbeing and relationships with peers.

• The hours per week spent in early childcare at age two do not appear to impact on behavioural outcomes and around 20-30 hours per week may even be positive for emotional development and wellbeing

• Centre-based early learning services should be aware of the increased risk of common childhood infectious illness for infants and toddlers and are strongly encouraged to follow regular hand washing with soap and to keep sick children away.

• There is a need for public health agencies, such as the Ministry of Health and District Health Board public health units, to work more closely with the early childhood education sector to ensure a reduction in ear, chest and gastro infections.

• Delaying the start of ECE until after the first birthday may help to avoid serious childhood infections and the prescribing of antibiotics and hospitalisation in infancy.

• Childcare centres and government policy should support and enable mothers to continue breastfeeding for as long as possible to aid the immune system in infancy.