LABOR candidate Lydia Senior has questioned the integrity of the House of Representatives vote in the seat of Mallee.
Ms Senior said The Nationals' state director Jenny Hammett had authorised a series of half-page advertisements in newspapers across the electorate in the lead-up to the election misleading Labor voters.
The advertisements asked people to consider allocating their second preference vote to Nationals candidate Andrew Broad.
Genuine Labor party preferences favoured the Liberal Party ahead of The Nationals.
Ms Senior said some voters confronted Labor volunteers and fellow candidates about the ads at the polls.
She said other people might have been deceived.
"It could create a huge precedent for future election campaigns and throw the whole thing into disrepute," she said.
Voters are still waiting for someone to officially be announced Member for Mallee.
The Australian Electoral Commission is recalculating the electorate's two-candidate preferred results.
At 1pm, Mr Broad held 58 per cent of votes, while Liberals' Chris Crewther had almost 42 per cent.