With fewer and fewer births and more elderly citizens, Japan could see its population fall 30 per cent to under 90 million by 2055, a government report said Wednesday.

Japan's population, now about 127.7 million, has already begun to shrink, unlike the population of Canada (which is increasing by about one per cent a year, thanks mainly to immigration) and Liberia (rising nearly five per cent annually to lead the world).

In 2005, the Japanese population declined by an estimated two-tenths of one per cent after a long slide toward zero growth.

The latest report, issued in Tokyo by the Health Ministry, does nothing to ease fears of looming labour shortages and runaway health-care and pension costs for a fast-aging population.

The ministry sees the country's population falling to 89.93 million in 2055, assuming the birth rate stays at about 1.26 children per woman over her lifetime, far below the rate at which each generation would replace itself.

The birth rate — at record lows in recent years — has left Japan with one of the world's most rapidly aging populations.

The number of Japanese 65 or older is expected to rise to about 36 million in 2055 from 26 million. Seniors would then account for about 40 per cent of the population, up from the current 20 per cent.

The working-age group (15 to 64) is forecast to drop to about 46 million, or just over half of the population, from 84 million or 66 per cent.

"It's imperative that we pursue effective measures to combat the falling birth rate now," the report said.

Canada's population grew by about 324,000 to an estimated 32.6 million between July 2005 and July 2006. About two-thirds of the increase was due to immigration.

Statistics Canada projects a population of about 42.5 million by 2056 under what it calls a medium-growth scenario. It sees seniors accounting for 25 to 30 per cent of the population at that point, up from the current 13 per cent.

With files from the Associated Press