People dressed in traditional attires were seen in queues before polling booths in all the five hill districts of Ukhrul, Senapati, Chandel, Tamenglong and Churachandpur, where central security forces have been deployed in strength.
Chief Electoral Officer O Nabakishore said all deputy commissioners of hill districts have been instructed to take every precautionary measure.
A total 10 contestants from BJP, Congress, Trinamool Congress, Naga People's Front, NCP, JD(U) and Aam Admi Party, besides three independents are in the fray.
The candidates whose fate is being decided today are sitting Congress MP Thangso Baite, Gangmumei Kamei (BJP), C Doungel (NCP), Kim Gangte (TMC), Soso Lorho (Naga People's Front), L Gangte (JD-U) and M K Zou (AAP).
The last phase of polls in the state will be held on April 17 for the Inner Manipur seat.