Tony Abbott is expecting the election debate "worm" to dislike him on Sunday night.
The opposition leader returns to Canberra late on Saturday and is preparing his arguments ahead of the National Press Club contest with Prime Minister Julia Gillard.
Unlike previous debates, the Liberal Party has dropped its aversion to the use of audience metres.
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But Mr Abbott is still expecting the worm to be unkind to him, based on former prime minister John Howard's experience in election debates.
"Obviously I've been thinking about it," he told reporters in Perth on Saturday.
"Certainly I know the worm dislikes Liberals, the worm's always hated Liberals, and I suspect that the worm's not going to change its character.
"So I'm expecting to see a pretty unenthusiastic worm tomorrow night, but I know that I have good arguments on my side."
Liberal party drops 'worm' objection
After initially opposing the idea, the Liberal Party has dropped its objection to the use of a "worm" in the only leaders' debate of the federal election.
Ahead of the Sunday contest between Prime Minister Julia Gillard and Opposition Leader Tony Abbott, the National Press Club has lifted its previous restriction on television networks using response meters to gauge audience reaction.
The agreement between the Labor and Liberal parties means there won't be a repeat of the 2007 debate controversy, where the Nine Network used a "worm" in contravention of the rules.
As with previous debates, the Seven and Nine networks and Sky News will show clean footage from the ABC.
The ABC's new 24-hour news channel will also broadcast the one-hour debate, scheduled for Sunday, 6.30pm AEST. Earlier in the year, Mr Abbott was seen to be judged harshly by the worms of different networks when debating health policy with former prime minister Kevin Rudd on television.
Even Hey Hey It's Saturday had Mr Abbott receiving a good dip in the worm's tail this week.
Sky News to moderate debate
Sky News political editor David Speers will moderate the contest, which will go to air an hour before the start of the season finale of ratings juggernaut Master Chef.
The leaders will also be grilled by a panel which includes ABC Television's Chris Uhlmann, the Australian Financial Review's Laura Tingle and the Daily Telegraph's Malcolm Farr.
The debate will open with a three-minute statement from the leaders.
They will be barred from carrying props or documents on to the stage and must keep their answers to three minutes.
Ms Gillard and Mr Abbott won't get to ask each other direct questions, but each will be allowed one minute to rebut points raised by their opponent.
A coin toss will determine who speaks first and who makes the first closing statement.
Pooled media photographers are banned from taking photographs during the debate and will be confined to capturing video images of the leaders and the panellists.
The major parties have agreed not to use any debate footage in election campaign advertisements.
They also made a deal with the National Press Club on the debate's format.
It will cover, in no particular order, the campaign issues of the economy, foreign relations and border security, health, education, environment, small business, rural and regional
Australia, and job creation.
Political parties' representatives and members of the parliamentary press gallery and the National Press Club will be in the live audience.
The coalition had wanted three debates, but Labor insisted on only one.
