The Papua New Guinea Electoral Commission has condemned the attack on five electoral officials by more than 500 people near Mendi.
The Post Courier reports the officials were on their way to take part in the changeover ceremony of the provincial election manager of the Southern Highlands.
The Chief Electoral Commissioner Patilias Gamato said the Acting Deputy Electoral Commissioner of Administration and four others were travelling for the ceremony to replace David Wakias, when they were stopped by people in 20 vehicles a few kilometres out from Mendi.
Mr Gamato said the people blocked the road, assaulted a senior manger, pushed female officers and threatened to attack them with knives and stones.
The women had their personal belongings searched and money stolen.
Mr Gamato said the attackers asked the group why Mr Wakias was being replaced and he has condemned the attack in the strongest terms and appealed to the public to respect the Electoral Commission officers as they carry out their constitutional duties.
PNG is due to hold its general elections next year.