The society would extend the ban to children’s playgrounds, alfresco dining areas, parks, squares and outside school gates.
The report states that the introduction of a smoking ban for all enclosed public places in 2007 was a “landmark in government interventions to reduce smoking levels, reducing the public’s exposure to harmful second-hand smoke, and acting as a catalyst for many smokers to ‘kick the habit’”.
Pro-smoking group Forest said the extension could lead to pubs closing. Simon Clark, director of Forest, said: “Banning smoking outside pubs and bars would discriminate against adults who enjoy smoking.”
The RSPH report said enforcing the measure would "denormalise" and reduce the convenience of smoking, encouraging smokers to quit.
The society backed up its proposal with research finding that in the year following the smoking ban 400,000 people gave up smoking.
Shirley Cramer, the body's chief executive, said: "Children are hugely receptive to the behaviour of the adults around them. The sight therefore of individuals smoking at prominent locations risks teaching them that smoking is a normal and safe habit.
"We believe that banning smoking in these locations via an exclusion zone could further denormalise smoking, ensuring that it is seen as an abnormal activity and potentially, prevent children and young people from beginning in the future."
The Welsh Government plans to give powers to ministers to ban smoking in extra public spaces, such as children’s playgrounds, which could affect beer gardens.