The Liberals and Labor have frozen out Fraser Anning's far-right party in the ACT's how-to-vote sheets as pre-polling began in Canberra on Monday.
Labor, the Liberals and the Greens have told voters to allocate no preference to Fraser Anning's Conservative National Party when voting for Senate candidates.
Voters headed to pre-polling booths around the national capital as party volunteers and candidates handed out their how to vote sheets.
Both major parties put the United Australia Party ahead of each other, as national polling shows Clive Palmer's $30 million campaign ad spend has gained traction.
The Liberals have directed voters to give their second preference to the United Australia Party, while Labor put the party ahead of the Liberals, which are last on the ALP's how-to-vote sheets. The Liberals have placed the Greens last.
Labor put the Greens second on how-to-vote sheets in the ACT.
While the Greens have told voters to put Labor second in the Senate vote, it recommended they put the ALP behind the Australian Progressives on lower house ballot papers.
Independent centrist ACT Senate candidate Anthony Pesec said he did not enter any preference deals with other candidates and would not recommend any preferences.
"As an Independent I want my supporters to make their own decisions about where their preferences should go in the ACT Senate contest," he said.
Mr Pesec, seen as a credible challenger for one of the ACT's two Senate seats, also targeted the nationalist candidates appearing on ballot papers.
"The one recommendation I will make is that the people of Canberra firmly reject the divisive extremism of Fraser Anning's Conservative National Party," he said, adding that voters should leave the far right party's box blank.
The Conservative National Party is fielding two Senate candidates in the ACT.
While many are watching Mr Pesec's campaign, the Greens are arguing they are the most powerful threat to Liberal senator Zed Seselja's hold on the ACT's second Senate seat.
Prime Minister Scott Morrison has faced questions about the Liberals' preference deal with Mr Palmer's United Australia Party, which could help hand back the minor party crossbench influence in the next parliament.
Labor has criticised the preference deal, however Mr Palmer said he had received several calls from ALP senator Anthony Chisholm. Opposition leader Bill Shorten said his party held no "formal" discussions on preferences with the United Australia Party.
A Liberal party spokeswoman said preferences were ultimately a decision for the party organisation but there would be no policy deals in exchange for preferences.
It is predicted that Australians will vote early in record numbers this election.
About 17 million people are enrolled to vote, and the participation rate has grown from 95 per cent in 2016 to 97 per cent.
Voters have the choice of numbering at least six boxes above the line, or at least 12 candidates below the line, when voting for the Senate. In the House of Representatives race, voters have to number every box on the ballot paper.