Woongjin Coway said Thursday it filed a complaint with the Fair Trade Commission against LG Electronics’ sales outlet chain, accusing it of spreading false information about its water purifier products.

Woongjin Coway, the nation’s top maker of water purifiers, has continued to criticize the electronics giant for entering its business two years ago. Water purifiers were excluded from the latest list of business areas that should be left for only small and medium-sized companies announced by a government-backed panel.

Woongjin claims that five LG Bestshop stores made their staff give out false information to customers that only LG products had received certification for sterilization and can filter 40 harmful substances while Woongjin’s can filter only five.

“All of this is untrue,” a Woongjin official said.

“LG Bestshop staff are known for comparing LG’s new products with old Woongjin products which stopped being manufactured more than seven years ago. Their unethical sales activities have crossed the line.”

LG Electronics denies the accusation, saying its staff never lied about rival companies’ products.

“Woongjin should stop the exhaustive arguments if it is confident about its products,” an LG official said. LG has insisted that Woongjin Coway, with annual sales of over 1 trillion won, is a large company too.

Woongjin last month called on LG to stop airing a television commercial which it claimed denigrated Woongjin’s water purifiers.

Woongjin said that the expression used in the commercial ― “Water put in a plastic tank is for washing, not drinking.” ― attacked its water purifiers, which use plastic tanks.

LG recently removed the line, saying the decision had nothing to do with Woongjin’s request.

By Kim So-hyun (sophie@heraldcorp.com)