'We will lose at least 30 per cent of business for sure,' he said. 'Most of our customers are smokers who come at night, and they count for 70 per cent of our business.

'The economy is just beginning to improve and we are just starting to get a taste of recovery after going through Sars and deflation in the past few years.

'The government is just shifting the responsibility of execution to us. Our staff members' safety might be in danger in the face of bad-tempered smokers. What can they do?'

Mr Lock urged the government not to push the law forward without careful consideration.

He also criticised the government for lack of consultation with the industry, saying the ban had not been discussed since the release of the first consultation paper on the issue in 2001.

'We told the government it could not act alone and it must work with us and educate the public gradually, but it seems the government is not listening,' he said.

Chan Wai-tsuen, owner of the New Tak Hing Restaurant in Wan Chai, said she would lose 'at least 20 per cent of my customers'.

'When they smoke, they can relax. They like drinking tea or coffee and have a smoke,' she said.

'I have been running my restaurant for years and it is hard for my customers to stop smoking all of a sudden. I really cannot afford to lose even one customer.'

Ms Chan was also worried about the execution of the policy, as most of her staff were smokers.

'How can the government expect the frontline workers who are smokers themselves to enforce the law? If other employees cannot stand the smoke, they should change their jobs,' she said.

The government should not just enjoy the tax revenue from selling cigarettes and then create problems by banning smoking in restaurants, Ms Chan added.

Japan Tobacco Hong Kong's corporate affairs officer Berky Kong Yee-wan said the company would follow whatever laws the government implemented.

'We have no stand about the issue and we will not comment on a law which affects other industries that we do not know much about,' she said.

Philip Morris Asia's corporate affairs manager Rebecca Ng Yuen-man said her company agreed with the law and was looking forward to working with the government.

MAIN POINTS

- Statutory ban on smoking extended to all restaurants, bars, karaokes, child care centres, schools, tertiary institutions, elderly and nursing homes, other indoor work places and indoor public places

- Sale of tobacco products with any promotional product banned

- More restrictions on tobacco branding at sponsored events

- Health warnings on tobacco products can contain pictorial and graphic content

- Warnings to take up at least half the largest surface of packaging

- The words 'light', 'mild' and others suggesting a lower health risk banned from packaging