US President Joe Biden speaks to media about the Democrats keeping the Senate before the Association of Southeast Asian Nations (ASEAN) summit, Nov. 13, 2022, in Phnom Penh, Cambodia. Photo: VCG

US President Joe Biden celebrated the strengthening of his party's majority in the Senate on Tuesday after Democrat Raphael Warnock was declared the winner of a runoff election in Georgia.

The incumbent senator defeated Republican Herschel Walker, a former football star and protege of former president Donald Trump, according to projections by television networks.

Warnock's win confirms the very slim Democratic majority, 51 to 49, in the upper house of Congress.

"Tonight Georgia voters stood up for our democracy, rejected Ultra MAGAism, and most importantly: sent a good man back to the Senate. Here's to six more years," Biden tweeted.

The party's electoral triumph does not change the balance of power in the Senate, of which Democrats had already secured control on November 8.

But the win by Warnock, a pastor at the Atlanta church where civil rights leader Martin Luther King Jr once preached, hands Democrats greater control in committees and curbs the power of any individual Democratic senator to sink Biden initiatives.

The Republicans took back the House in November but with a much smaller majority than expected.

Democrats retained control of the Senate in that vote with 50 seats, Vice President Kamala Harris's tie-breaking vote giving them the edge in the 100-seat chamber.

Warnock's win significantly curbs the power of centrist Democratic senator Joe Manchin, who has already blocked several major Biden initiatives in the first two years of the president's term.

With 700 days to go before the 2024 presidential election, Republicans hope to stymie Biden's momentum after his party performed much better than expected in November.

Determined to win the race, Democrats called on their top gun: charismatic former president Barack Obama, who campaigned alongside Warnock in Atlanta last week.

And in yet another sign of how high the stakes were, a total of $400 million was spent on the Georgia race to make it the most expensive campaign of the midterms.

Some 1.9 million people voted early, many of them likely Democratic voters, while Republicans were expected to turn out in force on Tuesday.

AFP