The Provisional Minimum Wage Commission, which was tasked to advise the Chief Executive on the initial statutory minimum wage, will announce the rate only after the bill is passed by legislators, a government official familiar with the issue said.

Unionist legislator Lee Cheuk-yan said he was keen to know the rate before the bill is passed.

'With the rate disclosed, we will really know how many workers will be protected, how many families in Hong Kong will get relief,' Lee said.

Unions across the city have been demanding a minimum wage of no less than HK$33 an hour, which they say is vital to improve the lives of many low-income workers and halt a widening gap between the rich and poor.

But most business groups and employers are pressing for a lower rate of about HK$25 an hour, claiming that a higher rate would cause many businesses to fold.

A study published by the University of Hong Kong's public opinion programme last month showed more than 60 per cent of respondents believe the minimum wage should be no less than HK$30 an hour.

Lee noted that there were only two obvious changes to the bill. The rate is to be reviewed every two years - a compromise on union demands for an annual review. And the minimum wage will not cover university students doing internships of less than 60 days.

'Of course, we would love to find out the initial rate first, but then I fear that if we insist on this it may mean workers will have to wait longer. So we will pass the bill first,' Lee said.

Wong Kwok-kin, another unionist lawmaker, agreed. 'We cannot let this drag on anymore. If we do not pass the bill within the current legislative session, God knows how long workers will have to wait for wage protection,' he said.

Dr Chung Kim-wah, an assistant professor of applied social sciences at Polytechnic University, said he was surprised the rate would only be disclosed after the bill has been tabled in Legco.

'It is so strange. I thought that the bill would be discussed when the rate is known,' he said. 'I cannot help but think it may mean the rate will be well below expectations ... it may be as low as HK$25 an hour.'

The Labour Department would not confirm when the rate will be disclosed. 'The Bills Committee of Legco is examining the minimum wage bill. We are working closely with the Bills Committee to facilitate the early passage of the bill,' a spokeswoman for the department said.

The spokeswoman also said the Provisional Minimum Wage Commission was working on its recommendation for the initial minimum wage rate with reference to official data and views from stakeholders. It will submit the recommendation to the Chief Executive by the end of the summer recess, she said.

Although the bill is expected to be passed on July 14, the government has said it will not take effect until the beginning of next year.