Aziz Ibrahimi, a spokesman for the Independent Election Commission, said that the employees were in the district of Maruf conducting voter registration, when Saturday night's attack occurred.
Aman said at least four Afghan security officers were also killed.
The Interior Ministry said in a statement that security forces killed 25 Taliban fighters when repelling the assault.
The Taliban, through a spokesman Qari Yusouf Ahmadi, claimed responsibility for the attack in Maruf.
Separately, Taliban attacked the police security cordon protecting the capital city of the western Farah province, killing four security officers, said Shah Mahmmod Nahimi, a provincial council member.
He added that four other security officers were wounded in Saturday night's attack in Farah city.
In the same province on Saturday, Taliban attacked army checkpoints in the Bala Buluk district, killing five and wounding seven others, said a local councilman, Abdul Samad Salehi.
Taliban have stepped up their attacks against Afghan security forces as the seventh round of peace talks between the U.S. and the insurgents is underway in the Middle Eastern state of Qatar.