The National Assembly passed the bill by a 208-0 vote. It will come into effect after a three-year grace period and after it receives final approval from President Yoon Suk Yeol.
Breeding, selling and slaughtering dogs for their meat will be punishable by up to three years in prison or 30 million won ($23,000) in fines.
Dog meat has long been a part of South Korean cuisine, and at one point up to a million dogs were believed to be killed for the trade every year, but consumption has sharply declined recently, as Koreans embrace pet ownership in droves.
Eating dog meat is something of a taboo among younger, urban South Koreans, and pressure from animal rights activists has also been mounting on the government to outlaw the practice.
Official support for a ban has grown under Yoon, a self-professed animal lover who has adopted several stray dogs and cats with First Lady Kim Keon Hee — who is herself a vocal critic of dog meat consumption.
Activists welcomed the bill, calling it “history in the making”.
“We reached a tipping point where most Korean citizens reject eating dogs and want to see this suffering consigned to the history books, and today our policymakers have acted decisively to make that a reality,” JungAh Chae, executive director of Humane Society International/Korea, said in a statement.
“While my heart breaks for all the millions of dogs for whom this change has come too late, I am overjoyed that South Korea can now close this miserable chapter in our history and embrace a dog-friendly future,” she added.
In a new survey released on Monday by Seoul-based think tank Animal Welfare Awareness, Research and Education, nine out of 10 people in South Korea said they would not eat dog meat in the future.
Previous efforts to ban dog meat have run into fierce opposition from farmers who breed dogs for consumption. The new law will provide for compensation so that businesses can move out of the trade.
Around 1,100 dog farms breed hundreds of thousands of dogs each year which are served in restaurants across the country, according to government figures.
Dog meat is usually eaten in South Korea as a summertime delicacy, with the greasy red meat — invariably boiled for tenderness — believed to increase energy to help handle the heat.
The country’s current animal protection law is intended mainly to prevent the cruel slaughter of dogs and cats but does not ban consumption itself.
Nonetheless, authorities have invoked the law and other hygiene regulations to crack down on dog farms and restaurants ahead of international events such as the 2018 Pyeongchang Olympics.
AFP