Nair is expected to lead mergers and acquisitions for the agency, as well as other business development initiatives.
GroupM confirmed Nair's departure for another WPP role earlier this month.
Nair, former MEC regional head and GroupM chairman in India, was handed responsibility for Southeast Asia in 2005.
According to Paul Davies, president at RMG Connect Asia-Pacific, Nair's appointment has yet to be confirmed.
