THE Mallee electorate's three independent candidates will band together when voters go to the polls for federal election next month.
How-to-vote cards for Ray Kingston, Cecilia Moar and Jason Modica will ask voters to preference independents as first, second and third on the ballot.
Ms Moar said the trio made the deal due to the National Party's historically large margin in the Mallee.
"We are combining our efforts to offer voters a one-in-every-70-years opportunity for change from major party rule," she said.
Mr Kingston said he had always planned to put independents first.
"After this, my preferences are entirely based on what I believe would be the best outcome for Mallee. There have been no other deals," he said.
Mr Modica is also set to preference the Nationals last.
The election is on Saturday, May 18. Mallee voters will have 13 candidates to choose from - the most of any electorate across Australia.
Only five candidates stood for the Mallee seat in 2016, when sitting Nationals MP Andrew Broad won comfortably. Mr Broad decided not to contest this election following a 'sugar baby' scandal in December.
At elections, a voter is required to number all the boxes on a ballot paper in order of their preference.
People who do not do this will not have their vote counted.
Dr Zareh Ghazarian, political lecturer at Monash University, said preferences would likely determine the Mallee's next politician.
Dr Ghazarian said the preference voting system meant that each candidates' votes would be distributed among the others, if they did not win enough votes to win.
"Eventually, all the preferences go to the final two candidates remaining, and the seat is decided on who has the 50 per cent-plus one votes needed to win," he said.
"We find that with the major parties especially, voters do follow the instructions given to them on the how-to-vote card. The key for the independents here will be to have their how-to-vote cards distributed across the voting centres - including the early voting centres.
"This is often a challenge for candidates who don't have the human resources major parties do."
An early voting centre opens at 72-74 Firebrace Street, Horsham at 8.30am on Monday, May 6.
Dr Ghazarian said a candidate outside of the major parties would need at least 30 per cent of the primary vote to win on preferences.
A spokeswoman for Labor candidate Carole Hart said she would put Mr Modica, Ms Moar and Mr Kingston second, third and fourth respectively. The Greens' Nicole Rowan said she expected to put Mr Modica second after the party's head office signed off on preferences this week.
Nationals candidate Dr Anne Webster will put Coalition partners the Liberals second and United Australia Party third.
Leigh Firman of the Science Party, Chris Lahy of the Citizen's Electoral Council and Dan Straub of the Shooters, Fishers and Farmers said they would not include preferences on their how-to-vote cards. Rick Millar of the United Australia Party and Phillip Mollison of Rise Up Australia said their head offices had not yet decided how they would allocate preferences.
Liberal candidate Serge Petrovich and Conservative National Party candidate Rick Grosvenor did not return calls before deadline.