Washington - Democrat Al Franken has won the US Senate seat for Minnesota, the state's election canvassing board said Monday.

Franken had been locked in a fierce battle with Republican incumbent Norm Coleman since the November 4 election, amid a heated recount of Coleman's initial victory by 215 votes out of more than 2.8 million votes cast in the upper Midwestern state.

In the recount, Franken won by just 225 votes, according to state election totals.

"After 62 days of careful, painstaking hand inspections, I am proud to stand before you as your next senator," Franken said after the result was announced.

Coleman had criticized Franken, who is best known as a comedian, for his lack of experience and crude jokes, while Franken has painted the moderate Coleman as a rubber stamp for Bush.

Dean Barkley, a third-party candidate from the Independence Party of former professional wrestler and one-time Minnesota governor Jesse Ventura, may have swayed the election, garnering more than 437,000 votes.

The victory gives the centre-left Democratic Party 59 seats in the 100-seat upper chamber of the US Congress, one shy of the 60 needed to prevent minority Republicans from blocking legislation through a parliamentary manoeuvre known as a filibuster.

The Minnesota Supreme Court earlier Monday rejected an attempt by Coleman to have more invalidated ballots included in the tally.

Coleman indicated through his lawyer that he would contest the decision in court. He alleges that some absentee votes were improperly disqualified and that in Democratic-leaning districts some ballots were counted twice.

Senate Majority Leader Harry Reid said in Washington that the drawn out contest was now over.

"The certification by the canvassing board, which has been in process for a number of weeks, now clearly shows that Al Franken has won. And based upon any of the allegations that Senator Coleman has made, there's no way he can catch up. That race is over," Reid said.