Endorsed by Lebanon's parliament last year, the law also bans tobacco advertisements, which have been criticised for luring young people into smoking.

Smokers caught lighting up in a closed public space face a $90 penalty, while restaurant or cafe owners who turn a blind eye to offenders could be fined anything from $900 to $2,700.

The number of smokers in Lebanon is among the highest in the region and cancer-related illnesses directly linked to tobacco are rising at a rapid rate, health professionals say.

Still, there is speculation as to how far the new ban can actually hold in a country where cigarette, cigar and nargileh (water-pipe) smoking is so popular and widespread.

Some 46 percent of Lebanese men and 31 percent of women are regular cigarette smokers, according to World Health Organisation figures that date back to November 2010.

Cigarette packs cost little over a dollar, a price even many Lebanese teenagers can afford.

But rather than focus on the potential health benefits, many have focused on the potential economic cost of the new law.

Lebanese restaurant and cafe owners have cried foul, warning that nargileh cafe owners especially will suffer.