An admission by Australia's opposition leader that he does not always speak the full truth has dealt a surprise gift to PM's Kevin Rudd's government.
Tony Abbott told ABC News that his off-the-cuff policy comments cannot always be taken as "gospel truth", but his carefully scripted remarks can.
He was being asked about a back flip on his promise not to impose new taxes.
Mr Rudd's Labor party, which is struggling in the polls, has nicknamed him "Phoney Tony".
In making the surprise admission while being grilled on a proposed new tax, Mr Abbot said: "Sometimes in the heat of discussion you go a little bit further than you would if it was an absolutely calm, considered, prepared, scripted remark."
"The statements that need to be taken absolutely as gospel truth are those carefully prepared, scripted remarks."
The government has seized on the remarks as evidence that Mr Abbott, who has made big gains in opinion polls, was not a credible leader.
Deputy Prime Minister Julia Gillard has labelled him "Phoney Tony", while her Labor party also rushed out a political attack ad.
"Next time Mr Abbott says anything, ask yourself, 'Is he telling the truth?' Because by his own admission, he's probably lying," the TV advert says.
Mr Abbott says the government is attacking him to try to escape its own political problems, saying he is simply trying to be "fair dinkum" - or honest - with the Australian people.
Mr Abbott, known as the "Mad Monk" because he trained as a Catholic priest, has a reputation for being gaffe-prone.
Last year, he compared the UN's Copenhagen climate talks to the Munich agreement signed with Hitler, and described climate change science as "absolute crap".