The Centre's decision overrules the contention of the Gujarat government that the matter was a state subject and that it has already appointed a Commission to probe it.
The Union Cabinet's decision came against the backdrop of fresh claims that the alleged snooping was conducted beyond the state of Gujarat.
The controversy broke out more than a month ago when two news portals released CDs of purported telephonic conversations between Modi aide and the then Gujarat Home Minister Amit Shah and two top state police officials relating to snooping on a woman.
The conversations, purportedly between August and September 2009, do not specifically mention Modi by name but refers to a “saheb”, which the portals claimed was the Gujarat Chief Minister at whose instance the snooping was done.