Adeeb was detained after his tugboat was intercepted by the Coast Guard near the coast of Thoothukudi in southern Tamil Nadu.
Ministry of External Affairs spokesperson Raveesh Kumar, answering a query on the issue, said: "There are designated entry points through which foreigners are allowed entry into India. The entry is facilitated on the basis of appropriate valid travel documents.
"In the instant case, since he was not entering India through a designated entry point and did not possess the valid documents, he has not been permitted entry into India."
Adeeb reportedly attempted to pass off as a crew member of the Virgo 9 tugboat.
An eyewitness shared a video of the apparent arrest.
Acting on a tip-off that the boat that went with nine people to the Maldives was returning with 10 people, authorities stopped the tugboat that was on its way to the Tuticorin port. On interrogation, it was found that the additional person was Maldives' former Vice President Adeeb.
According to Maldives news website 'RaajjeMV', Adeeb began his journey to India on July 27, via a tugboat. He was detained a day later, on July 28.
"A crew member of the tugboat he was travelling in has confirmed Adeeb's arrest to RaajjeMV, adding that he is currently under India's Bureau of Immigration's custody," it said.
Adeeb is facing trial in several cases including one related to an alleged plot to assassinate the then Maldives President Abdulla Yameen and for possessing firearms.
While Adeeb was sentenced to 33 years in prison over various charges including terrorism and corruption, he was freed earlier this year.
Prior to this, the former leader was granted medical leave to travel to India. Officers of the Maldives Police Service and Maldives Correctional Services had accompanied him on this trip.
Adeeb returned to the Maldives on July 6.
After he was granted permission to travel, the Maldives Supreme Court ordered authorities to seize his passport.
While the state has appealed the rulings that led to Adeeb's release, Supreme Court ordered Maldives Immigration to withhold Adeeb's passport until the court reaches a decision in the cases against him.