The head of water supplies said the government plans to raise water bills in a gradual and mild manner, noting there was a need to make a timely adjustment as the charges have stayed the same for nearly three decades.

Officials have been reviewing the charges since the start of the year, as part of a wider study on the cost recovery of public services amid a budget deficit.

In an interview with the Sing Tao Daily newspaper published on Monday, the Director of Water Supplies, Roger Wong, said besides recovering costs, the users' pay principle would also be a basis for the increase.

He noted the recovery rate of the water services operating accounts was at an historic low of 79 percent.

Water bills in Hong Kong, Wong added, made up around 0.1 to 0.2 percent of household expenditure, roughly a tenth of that in other advanced cities around the world.

The director stressed that people's affordability was a major consideration, but he didn't say when an adjustment might be made.

The Laundry Association chairman, Chau Hon-keung, said on RTHK that he thinks now is not the time to add to people's burden.

He said if charges are raised, the costs would surely be passed on to consumers.

"We have told the director [in a meeting] that if you haven't raised charges for so long, it's fair enough to increase them. But we don't think it's good timing, because everybody is finding things tough at the moment," Chau said.

"If there's no other way, then do it softly. Don't raise it by double digits as some organisations have done in the past...we hope the increase will be about five percent - rather than close to 10 percent."

Meanwhile, Simon Wong, who heads the Federation of Restaurants and Related Trades, said on the same programme that any minor increase would add tremendous pressure on the catering sector.

"Although water bills are not a big part of our operating costs, we are really worried [an increase] would lead to a chain reaction, such as raises in power bills, management fees and others that cause inflation," he said.

Wong said as some Hongkongers had been making trips north of the border for retail and dining, he thinks caterers wouldn't dare hike their prices if water bills went up.