Foundation cardiovascular health director Julie-Anne Mitchell said secondhand smoke could have serious effects on the health of non-smokers.

"The evidence shows that exposure to secondhand smoke in some outdoor areas is almost as risky as exposure in enclosed indoor areas," she said.

"The Heart Foundation advocates for smoking-free areas in places such as playgrounds, sporting fields, shopping centres and outdoor dining areas. There are numerous benefits to banning smoking in outdoor areas, particularly for children.

"It demonstrates that the majority of the public expect to be able to go outdoors and enjoy outdoor living without secondhand smoke; it reduces litter (from cigarette butts) and for people who are trying to quit, it strengthens their resolve."

Blacktown Council has banned smoking in children's playgrounds but does not have bans in place at sports fields, outdoor dining areas, parks or its pools.

Ms Mitchell said if the council strengthened its no-smoking policy to include those areas, it would be a step towards helping the population improve its health.

Blacktown councillor and Cancer Council regional chairwoman Kathie Collins said she "absolutely" supported widening the council's no-smoking areas.

"I will be looking at that very closely this year. Other councils are on their way to introducing no smoking in all their areas.

"Blacktown's health figures are simply the worst and that hasn't changed since the '80s. If we can reduce smoking and obesity we will be a healthier society."