The parties' platforms and "stable government" are the two greatest influences on how Australians plan to vote in Saturday's federal election, new Vote Compass data suggests.

The policy tool asked voters to nominate what was most likely to influence their decision: 30 per cent chose "party platform" and 23 per cent nominated "stable government".

University of Sydney political scientist Simon Jackman said the high level of people selecting "stable government" (23 per cent) was "clearly a vote for the incumbent".

"And that's clearly been a theme of the incumbent Liberal National Coalition this time around," he said.

When you break the responses down by how people plan to vote, it's clear the stable government message is resonating with people who plan to vote for the Coalition, while Labor and Greens voters are more likely to nominate the "party platform".

"Coalition voters are much more likely to nominate the party leader as the reason for their vote than are Labor voters," Professor Jackman said.

"That suggests that Malcolm Turnbull is playing more strongly within his base Coalition voters than Bill Shorten might be playing among Labor voters in this cycle."

Undecided voters don't know how they'll make up their minds

Among people who said they hadn't decided who to vote for on Saturday, almost one in three also didn't know what would influence their final decision.

"I think what you're seeing there is that last tail of the Australian electorate who are compelled to vote by compulsory voting, but if they were left to their own devices, probably wouldn't be engaging that much with the political system," Professor Jackman said.

"We're typically talking about not a lot of voters, but nonetheless they're there and in a tight election sometimes these things can matter."

Professor Jackman said voters' answers were not always the best guide to what actually influenced them.

"There's always a tendency with surveys of this sort for people to say something that sounds principled," he said.

"There's a little bit of that going on here that I don't think we should shy away from.

"Voting for the platform sounds way more principled than voting for the guy with the nice hair or the nice smile, or the girl with the nice hair and the nice smile so there's a bit of that going on."

Use Vote Compass to find out how your views compare to the political parties' policies.

These findings are based on 80,719 respondents who participated in Vote Compass from June 15 to June 24, 2016. The data has been weighted to ensure the sample reflects the Australian population. [ Read the Vote Compass data FAQ ]