Ahead of the release of an interim report into the state of the country's childcare sector, the Australian Competition and Consumer Commission said large number of families have struggled with expensive fees for services.

The watchdog has called for more parents to share their experience of childcare with the commission, before submissions close on Sunday.

The commission's chair Gina Cass-Gottlieb said more than 2000 families had already taken part, with similar stories emerging.

"The responses to this survey so far are creating a vivid picture of the issues families are struggling with and providing critical data for our analysis of the childcare sector and its costs and pressures," she said.

In some of the early responses, parents said they have had to join waitlists for childcare services more than a year in advance, in some cases before a child is even born.

The lack of a childcare place had forced many parents to delay their return to the workplace, or cause a reduction in the hours they work.

Respondents to the survey also described some of the childcare waitlists as "disorganised" and said that they "operate arbitrarily".

Many have also said they were refused service by childcare operators when approaching for support for a child with disabilities.

"We appreciate the experiences of families with children with disability are diverse and while this may not be the experience for all, it is an important preliminary insight from the parents and guardians survey," Ms Cass-Gottlieb said.

The Parenthood director Georgie Dent said the organisation was looking forward to the survey's findings later this year, but indicated more ambitious reform was needed.

"The interim survey findings that parents and guardians are concerned about lengthy childcare waitlists and increasing fees clearly demonstrate the need for a more universal, accessible and high-quality system," she told AAP.

"Australia needs an early learning system where every child has access to affordable and quality early childhood education and care.

"Access to more affordable childcare is critical for supporting more parents, especially women, to return to the workforce, helping to ease the cost of living and drive economic growth."

The inquiry into the childcare sector was announced by Treasurer Jim Chalmers in October last year, with an interim report to be handed down in June.

A final report is due to be completed by the end of the year, with families, providers and stakeholders being consulted as part of the inquiry.

Australian Associated Press