The Health and Safety Commission (HSC) has called for the government to go one step further and ban smoking in all public places, including non-food pubs.
It was responding to a government consultation on the current proposal, which would offer exemptions for pubs that do not serve food.
The HSC, which is responsible for the health and safety of workers, believes a full ban would make enforcement simpler and lead to greater benefits in public health, both for the public and workers.
Health charity ASH has welcomed the move. "We are delighted the HSC has backed the case for an end to smoking in all workplaces," said Deborah Arnett, director of ASH.
"It would be absurd and wrong for the government to recognise the health damage caused by second-hand smoke and then produce a law which fails to protect bar staff - the group of workers at most risk."
Cancer Research UK has also backed the HSC's decision. Jean King, Cancer Research UK's Director of Tobacco Control, said: "The HSC's response reinforces concerns that a partial ban will be confusing and difficult to enforce.
"It is clear support for comprehensive smokefree legislation is widespread, and we urge the government to drop its current plan to exempt pubs that do not serve food and private membership clubs.
"A partial ban would leave many thousands of workers unprotected, and could increase inequalities in public health."
However many in the pub industry believe a ban would decimate trade and are calling for the government to consider a third way involving exemptions for the hardest hit pubs.