WASHINGTON - REPUBLICAN Saxby Chambliss easily won a closely-watched US Senate run-off election on Tuesday in Georgia, denying Democrats a 60-seat 'super majority' that would have prevented Republicans from blocking legislation in the 100-seat chamber.

With 97 per cent of the ballots counted, Mr Chambliss led with 57.4 percent while Democrat Jim Martin trailed far behind with 42.6 percent of the vote, according to the Georgia secretary of state's website.

The runoff came nearly one month after the November 4 balloting in which neither Mr Chambliss or Mr Martin secured 50 per cent of the vote.

The Democrats needed to win the Georgia contest to reach the 60-seat threshold in the Senate that would have allowed them to cut off debate on bills and force votes, a commanding majority that would have strengthened president-elect Barack Obama's hand.

Tuesday's result meant that if Republican lawmakers maintain unity, they will have enough seats to use procedures to block or stall votes on key bills.

Turnout was much lower than in the November 4 election, with more than two million coming out to vote compared to about 3.7 million last month.

US media speculated that Democratic voters who had turned out enthusiastically to support Mr Obama for president last month had little interest in the run-off election.

Mr Chambliss had campaigned vowing to serve as a firewall against President-elect Obama and his Democratic allies dominating Congress, saying he would prevent them from having free rein.

'You have delivered tonight a strong message to the world that conservative Georgia values matter,' Mr Chambliss told supporters in his victory speech carried on television news networks.

'You have delivered a message that a balance of government in Washington is necessary, and that's not only what the people of Georgia want but what the people of America want.' The Republican victory leaves just one remaining Senate race undecided, in the midwestern state of Minnesota where ballots are still being recounted with Republican Norm Coleman ahead by just a few hundred votes out of some 2.9 million cast.

With Minnesota's race still up in the air, the Democrats now hold 58 seats, the largest majority the party has held since the 1970s.

The Georgia race attracted national attention and big money with high-profile figures hitting the campaign trail.

Former president Bill Clinton and former vice president Al Gore campaigned for Mr Martin and defeated Republican presidential candidate John McCain and his running mate Alaska Governor Sarah Palin stumped for Mr Chambliss - with Mrs Palin drawing big crowds.

Mr Obama did not travel to Georgia to help Mr Martin but did endorse him in a radio advertisement. -- AFP