People smoking in these places would be asked to move on or extinguish their cigarette, though there are currently no plans to fine punish those who do.
A public consultation in Manchester is due to start on the plans, with a decision expected to be reached in Autumn.
The proposals come after Manchester joined the Partnership of Healthy Cities – a worldwide group which seeks to tackle diseases like cancer and chronic lung disease. One of the requirements for membership is to have smoke-free outdoor spaces.
An estimated 5,000 people die from smoke-related diseases in Greater Manchester each year.