On Thursday, ACT auditor-general Michael Harris presented a report on referral processes for the support of vulnerable children to the speaker for tabling in the Legislative Assembly.

The maternal and child health service aims to visit all babies who are born in and live in the ACT when the newborn is between one and four weeks old.

The visits are intended to identify vulnerable children and families and refer them to additional support services.

But an audit has found up to 468 babies - or 10 per cent of those with a registered ACT address - did not receive the visit in 2018 "for a variety of reasons". Participation is voluntary for families.

"While this does not mean that mothers and children are not receiving appropriate health care, this represents a missed opportunity for ACT government agencies to engage with these children and their families, some of whom are likely to have vulnerabilities and who would benefit from attention from the maternal and child health service or referral to another program or service," Mr Harris said.

Following the first home visit, the maternal and child health service offers a further eight health and development checks at intervals until the child is four years old.

Mr Harris said there was "a poor take-up" of these additional visits, with participation generally decreasing between 2017 and 2018.

The audit report notes that children's experiences between birth and the age of five are particularly important in shaping their health, wellbeing and development into adulthood.

The audit made six recommendations including that Canberra Health Services should identify opportunities to improve take-up of the first home visit and the follow-up checks for children up to the age of four.

Other recommendations included that Canberra Health Services and the Community Services Directorate regularly report on identifying gaps in service pathways and how those were being addressed.