"In keeping with the new constitution, the president of the republic does not have the power to participate in the management of state and therefore I would not agree to become an honorary president," said Talabani.

"I refuse to present my candidacy in such circumstances," he added in a statement released overnight, two days before the election.

Iraq goes to the polls on Thursday to elect its first full-term parliament since the 2003 US-led invasion and the fall of Saddam Hussein.

The constitution, adopted at a referendum in October, limits the powers of the four-year head of stateship in order to guard against any return to the decades of authoritarian dictatorship experienced in the Saddam era.

"The president of the republic must be a real president, active in the leadership of the state, for the simple reason that Iraqis expect a lot from him," said Talabani.

"They address numerous demands to him, they call on him to end injustice and to help them solve their problems. If the president is honorary, he cannot respond to these demands."

The 72-year-old former rebel is leading the main Kurdish coalition running in the election, an alliance of his Patriotic Union of Kurdistan and Massud Barzani's Kurdistan Democratic Party.

His coalition, which along with the major Shiite group, the United Iraqi Alliance, has dominated the transitional government is expected to do well.

As head of the list, Talabani is poised to secure a top position in the subsequent political haggling, particularly with Barzani out of the election, content to remain president of the Kurdish regional government.

The first task of the elected 275 members of parliaments will be to appoint, by a two-thirds majority, a president and two vice-presidents.

The presidency council will then have 15 days to name a prime minister, who will form a cabinet to be put to parliament for approval.

A strong man who hates to be made a fool of, Talabani publicly reprimanded Shiite Prime Minister Ibrahim Jaafari, accusing him of violating Iraqi law and exceeding his authority by taking decisions without consulting the president.

A leader who cuts a popular figure in the new Iraq, Talabani has catapulted his people to the fore after years as second-class citizens.

A sworn enemy of Saddam, Talabani's mandate has seen him try to smooth strained relations with Syria and Iran, courting some disapproval in Washington which accuses the two of feeding the insurgency in Iraq.

An imposing, barrel-chested man, he has won praise for his efforts in walking a conciliatory line with Arab insurgents and disaffected Sunni Arabs who have largely boycotted the political process.

Head of the Kurdish list standing in the watershed election, he dresses impeccably in Western suits, has an unaffected manner and a sense of humour. His preferred catchphrase is: "My door is open all Iraqis".