At the top of their election campaigns, Australian Prime Minister Julia Gillard and opposition leader Tony Abbott have engaged early on in a debate on the economy, taxes, and migration issues.

In last night's leaders debate, Liberal-National coalition's Abbott, 52, criticised the Labour led- administration for acquiring too much debts and on the policy of granting refuge to asylum seekers arriving by boat with Gillard's vow to establish a regional processing centre.

"The government is threatening our economic future with a great big new tax on mining," Abbott said during the debate at the National Press Club in Canberra. "A strong economy is the foundation, the necessary foundation for a fair go."

The debate ahead of the national vote on Aug. 21 brought economic management to on top of the issues in a campaign dominated by the mining tax, immigration policy, population growth, and climate change.

A Newspoll published in the Australian newspaper today shows Abbott narrowing the gap on Labour after Gillard committed to delay taxing polluters until after 2012, postponing a pledge that was the mainstay of the Labour Party's election win in 2007.

Abbott gained 7 percentage points to 34 percent, according to the telephone survey of 1,720 voters on July 23-25 that was concluded before the debate, while Gillard's approval rating fell 7 percentage points to 50 percent.

Some 52 percent of voters prefer Labour compared with 48 percent for the coalition, trimming the 10-point gap recorded a week ago and returning to levels before Gillard ousted Kevin Rudd last month. The margin of error is 2.4 percentage points.