Smoking and vaping will soon be banned across more of Melbourne's CBD.

Melbourne City Council is investigating how to extend smoke-free zones across train station entrances and council-owned buildings.

The ban is currently in place across 13 outdoor areas, but could also come into effect at landmarks such as Town Hall, libraries and community sporting centres.

Lord Mayor Sally Capp said residents have been calling for the extension.

"We know that smoking is incredibly harmful, not just for smokers themselves but for recipients of second-hand smoke," she said in a statement.

"The City of Melbourne is working hard to ensure more residents, workers, visitors and families can enjoy our beautiful city without health concerns."

Melbourne City Council has no say over whether bans should be in force at state-owned buildings, including areas surrounding the MCG.

Signs across the city's existing smoke-free zones will soon be updated to explicitly ban vaping.

"We're confident this new signage will help minimise opportunities to use e-cigarettes in our municipality," Ms Capp said.

Quit Victoria estimates 19,000 Australians die from the effects of tobacco each year, but says there are no statistics on deaths linked to vaping.

"I think that we're still a long way off understanding ... the health risks associated with vaping," Quit Victoria director Dr Sarah White told AAP.

"The biggest concern with vaping at the moment is that it's a gateway to smoking, particularly for children.

"I think [the ban] is really great, because we hear from people all the time who tell us that they actually hate walking through those clouds of smoke or those clouds of sickly sweet e-cigarette aerosol."

Victorian Health Minister Mary-Anne Thomas said she was concerned about the health impacts of vaping in public places.

"We know that all tobacco causes harm. We take this issue very seriously," she told reporters on Tuesday.

"In terms of the decisions that Melbourne City Council are making, they are decisions for the council. But all that we can do to drive down the incidence of smoking, vaping and anything to do with tobacco, it's a good thing."