A wisecracking professional matchmaker breaks the ice as 40 people aged in their twenties and thirties gather at a hotel for a blind date.

Mass blind dates are common in South Korea but there's something unusual about this event in Asan: the city government is the one playing Cupid.

"Matchmaking is no longer a personal business, it's the duty of the nation," Yu Yang-Sun, a municipal official organizing the recent event, said in the city 90 km south of Seoul.

"Newborn babies are hardly seen here these days. If the young grow older unmarried and produce no kids, the nation will no longer have the basic human resources to sustain itself."

Asan's birthrate is 1.08, much lower even than the low national average, according to Ko Bun-Ja, one of Yu's deputies helping organize the event.

Five hours into the mass blind-date session, 12 of the 40 had decided to keep dating - much to the delight of city officials.

After years of promoting family planning in the nation of 48.6 million, South Korea in recent years has become increasingly alarmed at the prospect of an aging society - with a huge pensions bill and too few workers to sustain economic growth.

The government is increasing the number of nursery schools and providing more financial support - such as tax breaks or subsidized baby-sitting - for married couples who start families. Cash gifts are sometimes provided for newborns.

But the birthrate - the average number of babies born during a woman's lifetime - remained near the world's lowest at 1.19 last year. Fears are growing that the population will start shrinking within a decade.

Officials say the nation's low birthrate is partly due to more women joining the workforce and the lack of a comprehensive welfare system.

The high cost of child-rearing is also a deterrent.

Household spending on education reached an all-time high of 39.8 trillion won ($29.5 billion) last year, up 7.7 percent from a year earlier despite the economic downturn.

"This is a country where it's really uncomfortable to marry and raise children, given the shocking cost of education," said Bang Jeong-Ju, 30, one of the women on the blind date in Asan.

"My friends all say that if you cannot afford to give your kids a really good education, just don't get pregnant. Otherwise, pregnancy would be a sin."