A law which made adultery illegal in South Korea has been abolished - sending shares in condom companies shooting up.

The country's highest court struck down a decades-old law banning adultery, a statute critics argued infringed on personal freedom.

The law had been enacted in 1953 to protect women in a male-dominated society where divorce was rare. It made marital infidelity punishable with a prison sentence.

But it has been overturned after seven members of a nine-judge panel deemed the law to be unconstitutional.

'The law is unconstitutional as it infringes people's right to make their own decisions on sex and secrecy and freedom of their private life, violating the principle banning excessive enforcement under the constitution,' said Seo Ki-seok, a Constitutional Court justice.

Shares in Unidus Corp, which makes latex products including condoms, soared to the 15 per cent maximum price change that stocks are allowed to rise or fall in a given day.

Critics have said the law against adultery is outdated in a society where rapid modernisation has frequently clashed with traditionally conservative values.

In 2008, the court had upheld the law, citing the society's legal perception that adultery is damaging to social order.

Several thousand spouses file criminal adultery complaints each year in South Korea, although it is rare for someone to be jailed.

According to prosecutors, no one was put behind bars last year although 892 were indicted on adultery charges.