Concerns are being raised about the use of paracetamol in pregnancy.

A new University of Auckland study has drawn a link between the use of the pain-killer in pregnancy to behavioural problems in children.

Study leader Dr John Thompson says it's concerning to see there's a higher number of behaviour problems such as ADHD among these children years after their birth.

But he cautions more research is still needed to accurately measure the risk and consequences of using the drug during pregnancy.