"On the merger, the agency will closely follow and investigate for the benefit of the public and country," the agency's acting secretary-general, Trairat Wiriyasirikul, said in a statement.

Telenor and conglomerate CP Group on Monday announced an $8.6 billion deal to merge their Thai telecom units. The new entity would compete with market leader Advanced Info Service Pcl (AIS).

The agency sees this issue as important and may affect competition in the telecommunication industry and users, Thailand's National Broadcasting and Telecommunications Commission said in a statement.

"The agency will request that the companies clarify the need for a merger, the action plan and merger time frame, including the impact to users and the market, and potential remedies."

Telenor's chief financial officer Tone Hegland Bachke on Monday said the company was positive the merger would receive regulatory approval.

(Reporting by Chayut Setboonsarng; Editing by Ed Davies)