Hong Kong has one of the most rapidly ageing populations in the world. It also has one of the highest life-expectancy rates, with men living an average of 78.2 years, and women to the ripe old age of 84.1. And although this is a cause for celebration for us all, the speed with which this is happening is starting to cause some alarm.

Just 20 years ago, Hong Kong's population pyramid was shaped like a Christmas tree. The under-35s formed the majority of the population, followed by the under 20s, and retirees accounting for around 5 percent.

"Hong Kong was essentially a young city in 1981 and had relatively few old people," Peter HY Wong, member of the Elderly Commission, explained at the Chamber's June 4 seminar on "Retirees as a Resource."

In 2001, 16 percent of the population were aged under 15, according to statistics compiled by the Census and Statistics Department. This is projected to decrease to 12 percent in 2031. The ageing population trend will also increase the median age of the population, from 37 in 2001 to 46 in 2031.

"Since 2001, the prow of the pyramid has moved up so the middle-aged now form the bulk of the population. But the real shocker is the projections for the year 2031, which is becoming very top heavy," he says.

By 2031, an estimated 24 percent of the population will be over 65 years old, compared to 11 percent today, according to projections made by the Census and Statistics Department. Add to the mix an even longer life expectancy of 82.3 for men and 87.8 for women by 2031, and a fertility rate that has halved in the past 20 years, then Hong Kong is in for some serious population challenges.

Beyond the obvious challenges of providing social and health care services to care for these senior citizens, businesses may not be able to hire enough young talent to bring up the corporate ladder and drive their businesses forward, Mr Wong suggests.

"But why do we have to stick with the notion that you have to retire at 65? Modern medicine, good hygiene and regular exercise means that at the age of 65, people can have at least 20 years of productive life ahead of them," he says.

Mr Wong argues that it makes no sense to have a uniform retirement age. If people want to retire at 40, or at 80, then they should be allowed to do so.

"Many people of retirement age have much to contribute to society. Yes they should make room for younger ones to move up the corporate ladder, but companies should be looking how best to make use of their talents," he says.

Betty Yuen, Managing Director of CLP Power Hong Kong, also speaking at the seminar, said one of the keys to the company's success has been its ability to retain staff.

"When staff retire, all the expertise that they have accumulated over the years will be lost," she says.

One side-effect that recent corporate downsizing is expected to have on business is that as older workers have been encouraged to retire early, the expertise that they took with them will not be transferred to new staff when companies start hiring again.

"Industries are less willing to invest in human resources now as they look more and more towards profits, but it will take them a long time to recover all the expertise that they have lost," Ms Yuen says.

One option would be for companies to hire retirees as part time consultants. Both Ms Yuen and Nancy Chan, General Manager, Personnel Services -- Group Human Resources of Jardine Matheson, say their companies use such an arrangement to great effect.

"As we move forward, it will be necessary to employ older workers to fill the experience gaps," Ms Chan says. "So companies should be looking at ways to retain and use these staff."

The speakers suggest that government take the lead to counter the negative perception of older workers, and take steps to eliminate age barriers and discrimination.

"Employers must be willing to retain these staff and also retrain them," says Mr Wong. "Well educated and trained people are too good to waste."