The Qatari forces have not yet entered the country but were positioned at Yemen's border with Saudi Arabia, the source told AFP.
It was the first confirmation by an official in Doha of a report this week by Qatar's Al-Jazeera news channel that the country had sent troops to Yemen.
"We have sent troops who will be deployed along with Saudi troops," the official said.
"They are at the Saudi/Yemen border, they have not entered Yemen. They should be entering Yemen in the next few days."
This is believed to be the first time Qatari ground troops have joined the coalition, but the country's air force has previously taken part in the air campaign which began in March this year.
The deployment comes after a Friday missile attack by the Shiite Huthi rebels killed 60 coalition soldiers -- 45 Emiratis, 10 Saudis and five Bahrainis.