THE Nationals' Andrew Broad leads the Mallee's two-candidate preferred votes with 56.33 per cent of the electorate's support.
With all 110 of the seat's polling booths returned, the Liberals' Chris Crewther holds 43.67 per cent of votes.
About 10,000 votes separate the two.
Australian Electoral Commission Victorian director of operations Steve Kennedy said concerns for the integrity of votes in the Mallee had not been substantiated.
"Everything so far has been balanced and accounted for," he said.