The chat application has over 18 million users in Thailand, according to the media website Tech in Asia.
"No monitoring by the Thailand government has been conducted," Nam JiWoong, spokesman for South Korea-based Naver Corp, was reported assaying by Bloomberg financial news agency.
Thailand's Information and Communications Technology Minister Pornchai Rujirapa said his ministry was monitoring more than 40 million messages sent via the popular chat application in Thailand every day.
"We focus especially on those that are libelous, anti-monarchy, or threatening national security," he said.
Woong denied the claim, saying that LINE "considers consumer's privacy as a top priority."