Plans for a partial ban on smoking in public places in England are "unfair, unjust, inefficient and unworkable", an influential committee of MPs says.
Private clubs and pubs not serving food will be unaffected
The Commons health select committee says a total ban is the "only effective means" of protecting public health.
The Health Bill would allow smoking to continue in private clubs and pubs which do not serve food.
Health minister Caroline Flint said this represented "a huge step forward for public health".
'Element of choice'
She added: "Even in the exempted bars and private members clubs bar workers will be better protected through the exclusion of smoking in the bar area.
"We believe that these proposals offer the right balance between reducing the public health risk whilst allowing an element of choice for those who do want to smoke with a drink to do so in a way which has minimal impact on other people."
But the report says ministers, who have reportedly been divided over the issue, are "sorely lacking" leadership and clarity, while Cabinet attitudes have been "muddled and vacillating".
It calls for the ban on smoking to be extended to drink-only pubs and members-only clubs in an effort to protect bar workers and children from fumes.
A partial ban would "widen health inequalities" and "be disputed in the courts", MPs add.
The report - Smoking in Public Places - claims there is "clear public support" for a total ban and "strong evidence" of the effects of passive smoking.
The committee's chairman, Labour MP Kevin Barron, said: "The government is missing out on a golden opportunity to dramatically improve the public health of this country.
"The current proposals fly in the face of medical opinion and will do nothing to protect those most at risk.
"As they stand, they will simply exacerbate existing health inequalities and will confuse the public as to where they can and cannot smoke."
Tony Blair last week told MPs he would "listen to the debate with interest".
The committee found the Health Bill, published in October, had given "only a very vague sense of the government's intentions".
Health Secretary Patricia Hewitt has since said she expects the partial ban to lead to a comprehensive ban within a few years.
It is thought she wanted a total ban but settled for the partial option after meeting opposition in Cabinet from her predecessor John Reid, understood to be concerned it would lead to accusations of a "nanny state".
Some 95 MPs, including 64 Labour backbenchers, have signed a motion calling for a free vote on the issue.
Professor Alex Markham, chief executive of Cancer Research UK, said: "The government knows that pub workers will continue to die under a partial ban.
"We call on it to act on the views of doctors, health charities, the public and the hospitality industry and introduce a comprehensive smoke-free law as soon as possible."
The British Heart Foundation called the government plan a "nonsensical compromise".
However, a study by University College London suggests smoking bans in public places lead to children being exposed to higher levels of tobacco smoke at home.
The government has agreed to stop smoking in all pubs and clubs in Northern Ireland, and the Scottish Executive has ordered a ban.
The Health Bill gives the Welsh Assembly the right to decide for itself whether to implement a ban it has already twice approved in principle.