The polling percentage hovered between 39 to 46 per cent in the nine assembly segments of the Gurdaspur parliamentary seat till 3 pm.
The seat had fallen vacant following the demise of actor-turned-politician Vinod Khanna in April.
Voters could be seen standing in the queues at various polling booths across the constituency. However, a minor clash between Akali and Congress workers was reported from Pahra village in which five Akali workers including Happy Pahra, former village Sarpanch, sustained injuries.
The SAD accused the Congress, which is ruling Punjab, of threatening Akali workers. "Congress workers thrashed Akali workers in Pahra village today and no FIR has been registered yet," SAD spokesperson Daljit Singh Cheema alleged.
On the other hand, AAP candidate retired Major General Suresh Khajuria filed a complaint with the Election Commission (EC) alleging that a Congress worker was trying to influence voters inside a polling booth in village Pangoli in Sujanpur.
As many as 15.22 lakh voters are eligible to exercise their franchise in the by-election being fought by 11 candidates.
Around 30 companies of paramilitary forces and more than 7,000 Punjab police personnel have been deployed in the constituency.
The voting on the parliamentary seat started at 8 am and will go on till 5 pm.
A total of 1,781 polling stations have been set up at 1,257 locations, of which 457 have been declared as vulnerable and 83 as critical.
Voter-verified paper audit trail (VVPAT) is being used at all polling stations. Votes will be counted on October 15 and the result will be declared the same day, the official said.
The Gurdaspur Lok Sabha bypoll is being seen as a barometer to gauge the popularity of the six-month-old Congress government in Punjab.
The bypoll will indicate the popularity of the Amarinder Singh government which is battling allegations of reneging on its poll promises of farm debt waiver and free smartphones.
The Congress, which bagged 77 seats in the 117-member Punjab Assembly in February, is keen to keep the winning momentum going.
The BJP has also tried pulling out all the stops to retain the seat, which Khanna had won four times on its ticket.
AAP, the principal opposition party in Punjab Assembly with 20 seats, is also looking to strengthen its presence in the state.
The Gurdaspur Lok Sabha seat has nine Assembly segments -- Bhoa, Pathankot, Gurdaspur, Dinanagar, Qadian, Fathegarh Churian, Dera Baba Nanak, Sujanpur and Batala. The EC has allowed the use of alternative identity cards for the by-poll.
(This story has not been edited by Business Standard staff and is auto-generated from a syndicated feed.)