"Not just President Trump but no leader of any country in the world speaks in such a manner," the president was quoted as saying.
"Such reports can be an insult to President Trump," he added, according to his spokesman Kim Eui-kyeom.
Moon's remarks follow news reports that claimed the US president may have asked South Korea to pay $1.2 billion as part of costs to maintain US Forces in Korea.
|Moon Jae-in (Yonhap)|
The earlier reports suggested the US president may have filed such a request with his South Korean counterpart in their latest bilateral summit held on the sidelines of the Group of 20 summit in Buenos Aires late last year.
President Moon noted the US president has occasionally spoken about the South Korea-US free trade agreement and the defense cost sharing program but never about detailed amounts or conditions, his spokesman told a press briefing.
The US maintains about 28,500 troops in South Korea, a legacy of the 1950-53 Korean War.
Earlier reports said Washington has asked Seoul to pay at least $1 billion for burden sharing, while Seoul remains reluctant to ask its own legislature for any more than 1 trillion won ($889 million).
In 2018, South Korea paid 960 billion won for cost sharing. (Yonhap)