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OPEC is the Organisation of Petroleum Exporting Countries.

Mr Bush, who flew halfway around the world to be in Australia, not Austria, for the APEC (Asia-Pacific Economic Cooperation) summit of world leaders, took to the stage at the Sydney Opera House.

He thanked Mr Howard for his introduction and for being such a "kind host" for the OPEC summit.

"I mean APEC summit," he said.

"I've been invited to the OPEC summit next year. The APEC summit."

The faux pas brought laughter from his audience.

As if that was not enough though, Mr Bush also botched the host country's name, referring to Mr Howard's visit to Iraq in 2006 as a thank you to "the Austrian troops there".

Mr Bush also stumbled over his pronunciation of Jemaah Islamiah, the regional terror network, but had no trouble with its abbreviation - JI.

Upon finishing his speech, Mr Bush took the wrong way off-stage and, looking slightly perplexed, had to be redirected by Mr Howard to a centre-stage exit.

But not before a veteran White House correspondent seized the opportunity to ask Mr Bush whether there had been any new message in his speech. Apparently misunderstanding the question, he bristled and asked, "Haven't you been listening to my past speeches?" before turning away.

White House aides later said Mr Bush had been joking and would not, in fact, attend an OPEC summit.

Mr Bush is no stranger to the occasional faux pas, and often jokes about his habit of mangling the English language.

One of his highest-profile gaffes came in May when, at a welcoming ceremony for the Queen, he nearly placed her in the 18th century.

Then there was the famous incident at the G8 summit in St Petersburg in 2006 when Mr Bush, unaware he was on camera, greeted British Prime Minister Tony Blair with the words "Yo Blair".

Mr Bush's sometimes muddled syntax and mispronunciation of words like nuclear ("nukular") have long been fodder for late-night TV comedians. But aides say his folksy style has helped endear him to Middle America.