Prosecutors in South Korea are seeking an arrest warrant for Samsung heir Lee Jae-yong as part of their probe into suspicions surrounding the top conglomerate's controversial merger of two leading affiliates in 2015.

On Thursday, the Seoul Central District Prosecutors' Office filed requests for Lee, along with two former executives of the group's now-defunct Future Strategy Office, Choi Gee-sung and Kim Jong-joong.

The Samsung Electronics vice chairman and two others face charges of unfair trading, price manipulation and violating external audit laws.

Prosecutors suspect Samsung management intentionally lowered the value of Samsung C&T while inflating that of Cheil Industries ahead of the merger, to help benefit the heir-apparent in his managerial succession.

The state agency also suspects alleged accounting fraud at Cheil affiliate Samsung BioLogics helped facilitate the merger, which ultimately assisted Lee in overhauling the group's governance structure.