An increasing number of Australian adults are overweight or obese, according to the latest national health survey.

The Australian Bureau of Statistics (ABS) report for 2007-2008 shows one-quarter of adults are obese, while 37 per cent are classified as overweight.

This marks a significant increase from the last time body mass index data was surveyed in 1995.

There was also an increase in obesity among children. Over the past 12 years the number of children who are obese has increased from 5.2 per cent to 7.8 per cent.

Seventeen per cent of children are overweight.

Statisticians travelled around city and country Australia to measure 22,000 people.

The results for 2007-08 found that 68 per cent of all Australian men were overweight or obese, an increase of 4 per cent since 1995.

The figures for women were worse, with 55 per cent of women now overweight or obese, rising 6 per cent.

The heaviest age group were people in their 60s and 70s, with a staggering 79 per cent of men in that age group overweight.

ABS director of health Michelle Marquardt says the figures are concerning because being overweight is a risk factor for heart disease and type 2 diabetes.

Despite growing waistlines, two-thirds of people surveyed said they exercised for fitness, with most choosing walking as their preferred activity.

Most of those surveyed said they felt healthy, though the majority had at least one on-going medical condition.

Drinking down

But it seems some public health messages are getting through, with a slight reduction in the number of people drinking at risky levels.

In the week before the survey was conducted, about 68 per cent of men and 51 per cent of women consumed alcohol.

About 13 per cent of these consumed alcohol at a harmful level.

Teenagers aged 15-17 years were also questioned about alcohol. The ABS found 24 per cent of boys and 16 per cent of girls had consumed alcohol in the week leading up to survey - some at a risky level.

Meanwhile, the number of Australians smoking dropped from 23 to 20 per cent.

One in five adults were smoking in 2007-2008, down from 23 per cent in 2004-2005.

For the first time the survey questioned children about smoking and found 7 per cent of 15-17-year-olds smoke.

Long-term problems

The survey also found that nearly 80 per cent of the population has one or more long-term medical conditions, such as eye sight problems, arthritis or asthma.

About 10 per cent of the population reported having a long-term mental illness and 2 per cent of the population had been medically diagnosed with some form of cancer.

About 4 per cent of Australians have diabetes. More than three-quarters of those have type 2 diabetes, while 10 per cent have type 1.

In general though, most Australians consider themselves to be healthy, with more than half the respondents declaring their overall health to be very good or excellent.