Sources said leaders of Pakistan People's Party, Awami National Party and the Jamaat-i-Islami candidates reached an agreement to disenfranchise women in the race for Lower Dir's provincial assembly seat, Dawn newspaper reported.
The newspaper's sources also said candidates reached accord through "local operators" instead of coming forward themselves because of Election Commission restrictions.
"The decision was taken at village Bandagai in Talash area of Lower Dir district," one source said. "But there is no written document in this regard and we also do not know that there are such arrangements in other areas as well."
Political parties have previously barred women from voting in the area and adjoining union councils.
Meanwhile, the BBC reported militants targeted electoral offices and polling stations Friday in different parts of Balochistan as campaigning ended ahead of Saturday's elections. Violence in the run-up to voting has left people dead and injured and property destroyed.
Multiple injuries were reported from several cities in the attacks, police officials said.
The election is to be Pakistan's first successful transition from one civilian government to another in its 66-year history.