If overweight or obese Australians don't start changing their diets and exercise more then they increase their risk of cancer, warns Cancer Council Australia.

Maintaining a healthy weight is critical to avoiding cancer, with body fatness now strongly associated with an increased risk of 13 different types of the deadly disease.

A review of more than 1000 studies, published in The New England Journal of Medicine, has linked an additional eight types of cancer to being overweight or obese.

These cancers include stomach, liver, gall bladder, pancreas, ovary, thyroid, meningioma - a type of brain tumour - and blood cancer multiple myeloma.

Strong evidence was already available to link being overweight or obese to cancer of the oesophagus, colorectal cancer, breast cancer in postmenopausal women, and uterine and kidney cancers.

Paul Grogan, Director of Public Policy at Cancer Council Australia, says we could assume that based on the new analysis, released by the International Agency for Research on Cancer (IARC), even more cases of cancer attributed to excess weight have been diagnosed in Australia than first thought.

It's already known that about 4000 cases of cancer diagnosed each year in Australia are caused by carrying too much body fat.

According to data released by Cancer Council Australia in 2015, one in 10 cases of colon cancer is directly attributed to excess weight and 26 per cent of endometrial cancers are attributed to being overweight or obese.

Mr Grogan says the new data adds to concerns they've held for many years.

"As a country we have been saying to governments for more than a decade that we need to increase awareness about this risk."

He says the reality is that most cases of obesity are attributed to poor diet and lack of physical activity and if nothing is done about this then more people are going to suffer from cancer.

"If we don't start changing the way that we eat and the way that we exercise and the way that we manage body fatness, it's going to be unsustainable," Mr Grogan said.