The Liberal Party has performed well in the Victorian electgorate of Mallee after fielding a candidate for the first time in 20 years.
But it is still looking likely that Andrew Broad will hang onto the seat for the Nationals, despite this year's three-cornered contest.
Officials will add postal and pre-poll votes to Saturday's totals this week to declare a final result by next Friday.
The Australian Electoral Commission's Steve Kennedy says two party-preferences were tallied as the ALP versus the Nationals but the Liberals have been a strong challenger this year.
"Mallee has now gone maverick so we've had to change (it's an electoral term) how we're going to do the distribution of preferences," he said.
"The other thing we're starting today is we recount everything.
"All those votes that were cast on Saturday at all the polling places throughout the Mallee. This happens in every electorate."
Mr Kennedy says the Nationals look likely to win the three-cornered contest.
"The Nats, the ALP and Liberals have all taken a very healthy number of votes," he said.
"The way it's panning out, the Nationals (are) looking pretty solid to retain the seat of Mallee but we've just got to get the distribution of preferences from the ALP and Liberal Party right."
The Nationals have held the Coalition's safest seat since it was first created in 1949.
However the 23 per cent margin may be eroded because of the Liberal challenge.
Liberal candidate Chris Crewther says he is not sure whether Labor preferences will boost his chances.
With 80 per cent of first preference votes counted, Mr Crewther has won 27 per cent of that vote.
Mr Crewther says he does not know whether Labor's decision to preference him over the Nationals has helped his numbers.
"I guess it would help for Labor to be preferencing Liberals above the Nationals, as opposed to Nationals above the Liberals," he said.
"But at the end of the day the preferences are up to the individual and at the same time, is Labor is not handing out how-to-vote cards, so preferences can sometimes be irrelevant."