Key worries

Labour shortages Need for elderly care Pressure to delay retirement Expensive pensions and health services

Fourteen countries in Asia have fertility rates below the "replacement level" - the average number of children required to replace the older generation, the experts told a seminar in Singapore.

This means there will be more dependent elderly with fewer children to look after them and a smaller workforce to pay for the care they need.

The elderly population has already overtaken the younger generation in Japan and will do so by 2020 in Singapore and 2035 in China, according to Bhakta Gubhaju of the United Nation's Economic and Social Commission for Asia and the Pacific (UNESCAP).

The shortage of carers will be compounded by the younger generation's propensity to work abroad, Mr Gubhaju told BBC News Online.

Rapid development

"The labour force in major eastern Asian countries will age faster than any population in history over the next several decades," according to Gui-Ying Cao of the Austrian-based International Institute for Applied Systems Analysis.

Mr Gubhaju explained that although the phenomenon is in part simply a factor of industrialisation, the problem is more dramatic than it was when the West was developing because contraception is now more effective and widely available.

A preference for boys in some countries will compound the problem

Mr Gubhaju said that once fertility rates have started to decline, they are very difficult to reverse.

He said Singapore's offer of financial incentives to families that have more children has not worked, because it is a question of individual choice and "it is very difficult to change their ideas".

He said that instead governments should put in place parallel programmes to deal with, rather than halt, the phenomenon.

Care facilities, social security, and pensions should all be improved, he said.

Mr Gubhaju added that the demographic changes could ultimately have a major impact on the region's economy.

In the short term the economic pressure will be born out of a need for more pensions and health care, but in the long term it will result from a shrinking workforce, he said.