More than 23,160 Canberran children were enrolled in formal childcare services in September last year, a 69.2 per cent rise on the same period in 2007 when 13,690 children were enrolled.

This contrasts to a nearly 40 per cent rise in enrolments nationally in that time, while NSW and Victoria recorded a 52 per cent rise, according to departmental figures released by Assistant Minister for Education Sussan Ley.

The figures also show the ACT was one of only two states and territories where the number of hours of childcare used by families per week has gone backwards, dropping to 22.9 hours from 24.6 hours in 2007.

Usage in NSW rose from an average 22.3 hours in 2007 to 23.8 hours a week last year, while Victorian children went from 21.9 hours to 25.2 hours.

The only other state and territory whose hours of usage also dropped was the Northern Territory.

In the six-year period to September 2013 fees rose by 53 per cent nationally, from $5 an hour to $7.65 an hour.

At the same time as demand surged, the number of services rose just 50 per cent in the territory, a pinch families have been feeling for some time with long waiting lists reported in many centres.

This is despite numerous attempts by the ACT government to boost places.

With births increasing in the capital for the last decade and another 6291 babies born last year, the squeeze is not expected to ease anytime soon.

Childcare worker union United Voice warned in July of a "perfect storm" brewing in the ACT, pushing already high demand through the roof due the the territory's high proportion of both parents working and lower unemployment.

Ms Ley acknowledged that childcare had become increasingly unaffordable for ACT families, which was why parents were choosing fewer hours of care.

"This is clearly having an impact on the number of hours of childcare ACT families can afford to access per week, which, in turn, reduces workforce participation opportunities, particularly for women," Ms Ley said.

A report released in December last year showed Canberra families were paying the greatest proportion of their income on childcare fees, compared to those in other states and territories.

Unions and academics said that difficulties with staffing made it hard for more places to be created.

Last week United Voice also said there was a mass "exodus" of childcare workers taking place, with about 180 workers abandoning the profession each week.

The union said "low pay and poor" recognition were to blame, which would "continue until this is fixed".

But the solutions are not clear. A 2013 NATSEM study into childcare affordability found that childcare was a "significant policy conundrum", since increasing subsidies also drove up prices for care.

The same study found childcare was costing Canberrans up to 8.9 per cent of their disposable income, as was the case in Gungahlin last year.

The Productivity Commission released draft recommendations last month suggesting the government establish a single means-tested childcare subsidy and that some of the funding from the Paid Parental Leave scheme be redirected to childcare.

The report said the cost of childcare was the most commonly reported barrier to getting parents with children under five years back into the workforce.

The Productivity Commission conducted public hearings in Canberra on Monday, which will continue on Tuesday. Public submissions on the draft report are encouraged and close on September 5.

The final report is expected to be handed to the government in late October.