New rules regulate marriage-by-mail brokers, participants in South Korea

South Korea has put new restrictions on mixed-ethnicity marriages, but critics say it would be better to focus on supporting foreign spouses who struggle to assimilate in one of Asia's most ethnically homogenous societies.

An influx of foreign brides - overwhelmingly from other Asian countries - began in earnest in 2000 and peaked in 2005, when more than 30,000 were given resident-through-marriage visas.

The trend was triggered by the large numbers of young, rural women leaving to find work and a new life in Seoul and other South Korean cities, leaving behind male-dominated communities with not enough potential wives to go around.

Since 2000, 236,000 foreign women have settled in South Korea through marriage, giving birth to about 190,000 children.

About 80 per cent came from China, Vietnam, the Philippines, Cambodia, Thailand and Mongolia - essentially "mail-ordered" through matchmaking brokers.

At first, South Korea did nothing to rein in marriage brokers, believing they were fulfilling a useful service helping to improve a radically declining birth rate and labour force in the countryside.