The seat had fallen vacant after the death of Pakistan Muslim League-Nawaz MPA Arbab Akbar Hayat.
Polling started at 8:00 in the morning and will continue without break till 5:00 PM.
In the contest for the Khyber Pakhtunkhwa Assembly seat 15 candidates are in the field including PML-N’s Arbab Muhammad Waseem, PPP’s Tehmas Khan, PTI’s Shahzad Khan and JUI-F’s Asif Iqbal Daudzai.
The constituency has over 150,000 registered voters including 56,000 women. The election commission has set up 97 polling stations in the constituency for polling.
Forty-one polling stations of the constituency have been declared as extremely sensitive.
The Army troops have been deployed inside and outside all polling stations, the ECP had announced on Wednesday.
The decision was taken on a request from the district returning officer and on recommendation by the provincial election commissioner, along with provincial authorities in order to ensure law and order during the by-polls.