A Picture of ACT's Children and Young People reveals that although young Canberrans' health, development and wellbeing are reasonably good, childhood obesity is worsening.

It is the fourth year the ACT Government has ranked the territory against national indicators compiled the data.

Overall, 26.3 per cent of ACT children aged five to 17 years old are overweight or obese, according to the 2011-12 Australian Health Survey.

The number of overweight Canberran children has climbed by almost four percent, from below the national average at 15.6 per cent to above the national average at 19.4 per cent.

In contrast, the number of overweight children across Australia has remained almost unchanged in the same four-year period, rising less than 1 per cent from 17.2 to 17.7 per cent.

Meanwhile the number of obese children rose less than 1 percent from 6.1 to 6.9 per cent. While the jump was much greater than the nation's 0.1 per cent rise, the figure still remains below the national average of 7.6 per cent.

Although parents are becoming more aware of their children's physical activity needs, less than half knew their sons and daughters needed at least one hour of exercise each day.

In contrast alcohol consumption has dropped significantly among Canberra youth.

The number of students who have consumed at least a few sips of alcohol has fallen by more than 10 per cent from 85.9 per cent in 2008 to 73.2 per cent in 2011.

At the time of the 2011 ACT Secondary Students' Alcohol and Drug Survey, 14 per cent of students had drunk alcohol in the last week compared to 24.2 per cent three years earlier.

Students drinking more than four alcoholic drinks on one occasion almost halved from 8.1 to 4.3 per cent.

Smoking rates among students have also dropped. In 2011, 19.1 per cent of all students surveyed reported having smoked at least once compared to 26.4 per cent three years earlier.

Almost six per cent of students smoked at least one cigarette in the week before the survey (5.8 per cent), while 1.4 per cent smoked every day.

Aside from weight, the ACT has also witnessed a rise in the number of developmentally vulnerable children, particularly among the Aboriginal and Torres Strait Islander community.

The proportion of vulnerability among indigenous children is double the proportion of total Canberran children, according to Australian Early Development Index Results.

The figure has increased from 37 per cent in 2009 to 45.4 per cent in 2012 despite a national decrease of more than four per cent to 43.2.

The proportion of vulnerable Canberran children, 22 per cent, was the same as the national average,

Although ACT children were least likely to be developmentally vulnerable with language and cognitive skills, more than 10 per cent of children were worse off in regards to physical health and wellbeing.

The gap between Canberra's indigenous and non-indigenous children and teenagers is also reflected in the numbers of young offenders and detainees.

The number of offending youths in Canberra has dropped to the lowest rate in the past four years, from 2573.2 per 100,000 in 2009-2010 to 1920 per 100,000 between 2012 and 2013.

But the ACT has the highest number of Aboriginal and Torres Strait Islander young people under supervision, despite a decline from 712.93 to 551.56 over the four years.

Less young people have been detained in the ACT's Bimberi youth justice facility, dropping from 136 youth in 2010-11 to 104 in 2012-13.

Almost four times as many men than woman were detained. A quarter of men and almost a fifth of women were of Aboriginal and Torres Strait Islander descent.

Other report highlights include an increase in the number of families accessing services from Canberra's child and family centres, a drop in the percentage of women smoking during pregnancy and a decrease in the rate of infant deaths.

As of June 2012 children and young people aged between 0 to 24 years of age comprised 33.7 per cent of the total population in the ACT, 126,196, while 2.8 per cent identified as Aboriginal and Torres Strait Islander.