Opposition Leader Tony Abbott is again urging people to steer clear of the minor parties and independents when they go to the ballot box.
He also warned voters the election "could still go either way".
"There are a lot of people who are toying with the idea of voting for independents or minor parties," Mr Abbott told the Seven Network as polls opened at 8am (AEST) on Saturday.
"My strong, strong request to them is don't, because we need a strong and stable government."
Speaking at Freshwater, in his Sydney electorate, Mr Abbott said the election was a referendum on the carbon tax and "on governments who don't tell the truth".
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If the coalition wins government, as expected, he said it would scrap the carbon tax and stop the boats.
"But we can only do that if people vote for their Liberal National candidate in the house and also in the Senate," he said.
"We need a strong and stable majority government in both houses if our country is to go forward."
It took just 15 minutes after polling booths opened for Mr Abbott to suggest Labor had been up to dodgy campaign tactics.
"There's been a massive last-minute blitz of phone calls and letter-boxing and dirty tricks from all sorts of people, but certainly the Labor party and unions have been very active," Mr Abbott told the Nine Network.
"There's 10 hours to go until the booths close and a lot can happen in 10 hours."
He said he didn't believe the most recent Newspoll that showed the coalition had opened up an eight per cent gap over Labor.
"I think it's still very close," Mr Abbott said.
