The discovery of the lead-based paint followed a warning last week to parents of children at the Heritage Childcare Centre next door to consider having their children blood-tested, after high levels of lead were found in two of 37 samples taken at that centre.

After the findings at the Heritage Childcare Centre, further testing was carried out at the University Preschool (UPCC), while inspections of interior areas of the centre in April and last week did not find any areas of risk for children.

The ANU last week said there were no concerns for lead-based paint at the UPCC, but the paint was discovered after maintenance staff removed hedges from the courtyard at the weekend, allowing a more detailed examination of areas previously inspected.

While the university has had some 73 samples taken from the centre, the results were not due back until Wednesday this week and it has closed the play area as a precautionary measure.

Some 117 children attend the UPCC and a further 85 attend the Heritage centre next door.

An ANU spokesman said in a statement that remediation work at the University Preschool centre had begun, and ACT Health's health protection service had been notified.

Vice-Chancellor Brian Schmidt said parents had also been told, and there would be a meeting for parents and university and health officials on Wednesday at 5pm.

"The health and safety of children at the University Preschool and Childcare Centre is our top priority and we have closed the central play area as a precaution," Professor Schmidt said.

"I fully understand as a parent whose children attended UPCC just how worrying news like this is. I can assure parents we are making every effort to ensure the children's safety and that we don't have this sort of issue ever again."

An environmental hygienist has also assessed The Cubby House on Campus Early Learning Centre and the Acton Early Childhood Centre on the university campus, but found "no cause for concern" at either of those centres.