Tokyo: Japan's health ministry is likely to drastically water down a proposal restricting smoking in restaurants, media said on Friday, a move that risks Tokyo becoming one of the unhealthiest hosts of the Olympic Games in years.

Japan ranks at the bottom globally in anti-smoking measures, going by the types of public spaces entirely free of smoke, says the World Health Organisation, which has teamed up with global Olympics officials to guarantee smoke-free Games venues.

Ahead of the 2020 summer Olympics, the International Olympics Committee (IOC) is among those pressuring the Japanese capital to follow Rio de Janeiro and other recent games hosts in banning smoking in all public areas.

IOC vice-president John Coats has said the body cannot force a ban beyond the venues and the Olympic Village, however.

The health ministry was forced this year to scale back a proposed bill for a blanket ban on public smoking in the face of opposition by pro-smoking politicians, restaurateurs and Japan Tobacco, which is one-third government owned.

But even the weaker bill foundered, due to opposition from the ruling Liberal Democratic Party (LDP).

In August, anti-smoking Health Minister Yasuhisa Shiozaki lost his job in a cabinet reshuffle. Reuters