Two organisations committed to achieving healthy communities have teamed up to tackle "increasing and alarming" obesity figures for the Illawarra.

Heart Foundation research released earlier this month showed that 26.9 per cent of Illawarra people were obese. The same research revealed that the state obesity average was 26.4 per cent and the national average was 27.5 per cent.

Healthy People Illawarra general manager Maree Kerr said obesity within the Illawarra was a growing concern.

"By providing people with free healthy eating programs coupled with physical activity, we empower them to make healthy choices, and as a result reduce their risk of chronic disease," she said.

Ms Kerr said the sister organisation of Healthy Cities Illawarra had joined forces with Chodat Fitness to launch The Winter Hump challenge to help people boost their healthy eating and physical activity for good health across the winter months.

The 13-week challenge by Chodat Fitness encourages participants be active by exercising regularly, focusing on team motivation and individual transformation challenges.

Chodat Fitness director Emily Chodat said the aim was to get more than 100 people taking part in the event, which was now in its third year.

"We have considerably lowered our prices to encourage people to join in team motivation and keep active during winter," she said.

"We feel our values of health, fitness and wellbeing aligns with that of Healthy People Illawarra. With our knowledge of fitness and health combined with some of the programs Healthy People Illawarra provide the overall health benefits of the communities that we reach can only increase."

Ms Kerr added The Winter Hump challenge was the start of an alliance which would add value to the communities of the Illawarra through future preventative health initiatives.

To register for The Winter Hump visit chodatfitness.com.au and follow the prompts.