Julia Gillard, leader of the Labor Party and Australia's first female leader, will formally launch her campaign next week for the national election on August 21.
She became prime minister just six weeks ago, after ousting fellow party member Kevin Rudd in an internal coup.
Abbott, a devoutly Catholic fitness buff, has capitalised on problems in the Labor Party.
"Just six weeks ago [Labor] politically executed its leader, effectively admitting it had failed [in government]," he said, drawing attention to Rudd's ruthless ouster.
"Why give the Labor Party a second chance when it wouldn't give its own leader one?" Abbott rhetorically asked cheering supporters at his launch in the state of Queensland.
While Abbott has a strong chance of unseating the government, the latest Reuters poll trends suggest Australia is facing an increasing chance of a hung parliament, its first since the second world war.
No Australian government since 1931 has lost an election after just one term in office.
Immigration is shaping up to be a major issue, especially in rural seats like eastern Queensland which will play a crucial role in tipping the balance of power.
Abbott pledged mandatory prison terms of at least 10 years for human traffickers, highlighting the fact that 150 boats carrying 7,000 people have arrived on Australia's shores since the Labour Party won power three years ago.
Gillard dismissed charges that her government had failed to take action against human smuggling.
"We've got mandatory jail sentences in the current legislation. We have a crackdown," she told a television audience.
Abbott also criticised the government's plan for a carbon-trading scheme, pledging not to "damage out economy with futile environmental gestures".
Gillard criticised the Liberals and defended her government's record on economic management, telling reporters that "None of the other major advanced economies avoided recession and we did".
But Labor has come under fire for trying to levy a tax on mining companies, which employ many Australians and form a back-bone of the economy.
Abbott told supporters that the mining industry under his government could "again do what it does best: creating wealth and employing hundreds of thousands of Australians without the threat of an investment-killing, jobs-destroying great big new tax".
The Liberal leader served as health minister under John Howard, the former prime minister who signed Australia up for participation in the US-led invasion of Iraq and lost an election to the Labor Party three years ago.
He is running under the banner, "Stand by for Australia, stand up for real action".