Papua New Guinea's electoral commissioner Andrew Trawen says reports of four ballot boxes being disqualified in the Anglimp South Wahgi by-election are yet to be confirmed.
The Post Courier reports that the ballot boxes were lost to candidates and their supporters, who used threats and guns on voters and election officials.
Mr Trawen says while he has been briefed by police about incidents, it's up to the returning officer to decide on the legality of the ballot boxes.
"I've yet to recieve information on what decision the returning officer's made. The decision lies with the returning officer; if he feels that it may have been tampered, then we'll look at it. It's too early to say whether the ballot box was declared invalid, or was declared illegal."
Andrew Trawen says overall, polling has progressed well in the first of three by-elections using the new Limited Preferential Voting system.
Polling has also started in Yangoru Saussia and Chimbu electorates.