Cancer Council NSW is calling on the government to protect children by removing junk food advertising from public transport.

More than eighty per cent of food ads on Sydney buses and at trains stations are for junk food, according to Cancer Council NSW, at a time of growing rates of childhood obesity.

Each month children under the age of 15 in NSW make over 3.3 million bus trips and over 2 million train trips. The Cancer Council's research found that one third of the food advertisements along their journeys on public transport services were for sugary drinks and one in five for fast food meals like burgers and chicken.

The research, which will be presented tonight at an event hosted by Sydney Health Law and Cancer Council NSW, also found that on buses alone, nearly 60 per cent of food ads were for popular fast food restaurant chains.

“This is extremely alarming as 21.4 per cent of NSW children aged 5-16 are now overweight or obese. If they carry that weight into adulthood that puts them at risk of 12 different cancers, as well as heart disease and type 2 diabetes,” said Cancer Council NSW’s Nutrition program manager, Wendy Watson.

The ACT Government has removed junk food advertising on buses, Watson says, and in Western Australia alcohol advertising has been banned on all public transport.

“Childhood obesity is currently a premier’s priority. If we want to see a real decline in overweight and obesity, this is one way a NSW Government can show leadership,” Watson said.

An annual $25 million in government funds was spent last financial year on combating childhood obesity in NSW, and Cancer Council NSW is calling out the government for sending contradictory messages, Fairfax Media reports.