Kirchner has put forward his wife Cristina, who is running for senator

Among those seeking office is Mr Kirchner's wife, Cristina.

Voters will elect representatives for half of the Argentine lower Chamber of Deputies and a third of the Senate.

Mr Kirchner came second in the first round of the 2003 presidential vote and won by default when ex-President Carlos Menem dropped out of the second round.

Campaigning ended on Friday, and no more rallies or polls are allowed before voting day.

"This is more than just an ordinary mid-term election," Reuters news agency quoted Graciela Romer, a Buenos Aires pollster, as saying.

"Two things are in play: Kirchner needs to size up his level of popular support, and (the vote) will also determine who is the undisputed leader of the Peronist party."

Mrs Kirchner is running for a senate seat in Buenos Aires province.

Her opponent is Hilda Duhalde, the wife of former president Eduardo Duhalde, who represents a rival faction of the ruling Peronist Party.

Polls suggest Mrs Kirchner should secure a comfortable victory.

The president, who won a mere 22% of the vote in the 2003 election, has been rallying in and around the capital almost on a daily basis.

He has been urging Argentines to support him in his effort to restore the country's economy after the 2002 meltdown, and hopes a victory of his candidates in Sunday's poll will increase his chances of being re-elected in the 2007 presidential elections.