Employment in the ACT's public sector has exploded by 30 per cent in six years, far outstripping the other states and territories.

The territory government wages bill has grown by $685 million in the same period, blowing out by $110 million each year.

New Australian Bureau of Statistics figures show the ACT's public sector grew by more than three times the combined national average for state governments and local councils.

Do you know more? Send your confidential tips to ps@canberratimes.com.au

Only local councils in Western Australia had more jobs growth over the period.

But the territory government says its workforce has expanded to keep pace with Canberra's rapidly expanding population and that it has to provide services undertaken by local councils in other jurisdictions.

An ACT government spokesman also said on Tuesday that much of the expansion of the public service had been in vital health, education and public safety roles.

The Canberra Liberals, who have long accused the Labor government of being unable to control its spending, did not respond to a request for a comment on the new figures.

The territory's public sector, which includes the government's public service and workers in all of its other agencies and fully owned enterprises, has grown from 19,600 workers in 2007-2008 to 25,500 in 2012-2013, the ABS figures show.

At the same time the public sector wage bill has grown from $1.2 billion to $1.87 billion.

Australia-wide, employment growth in the local, state and territory sector workforces has been less than 9 per cent since 2007-2008.

But late on Tuesday, a spokesman for Chief Minister Katy Gallagher defended her government's hiring record.

''The ACT government has invested in key areas of public service like health and education but has also responded to continued growth in our city's population,'' the spokesman said.

''The ACT government performs both state and local government functions and delivers on a range of services that are split amongst different levels of bureaucracy in other, larger states.''

The spokesman said that the growth in the public service - about 80 per cent of the broader public sector - was in line with community expectations of service delivery in health, education and public safety.

''As per the State of Service Report 2012-013 and the Workforce Profile 2006-07 over the six-year period from 2006-07 to 2012-13 the ACT public sector has grown from 15,733 to 19,793,'' the spokesman said.

''Over this period employment growth has included over 1700 health workers, more than 650 personnel in the education sector, approximately 200 in the community sector and approximately 600 in the area of justice and community safety, with a further 200 front-line staff appointed in territory and municipal services.

''This growth reflects the government's commitment in service delivery in areas of health, education and safety.

''As a proportion, over the past six years the size of the public sector has increased from 5 per cent to 5.3 per cent of the total ACT population.''