US mid-term elections: Republicans win Senate majority UPDATED

UPDATED 5.45PM NZ TIME: The Republicans have won the six seats they needed to wrest control of the Senate from the Democrats in the US midterm elections.

The voter swing to the Republicans began when Mitch McConnell, the Republican minority leader, won a sixth term in Kentucky, defeating Democratic opponent Alison Lundergan Grimes and confounding pundits who who said voters would turn against incumbents.

This did not occur with the Republicans, whose Mr McConnell, 72, will become the next Senate majority leader.

The significance for New Zealand is that Republican majorities in both the House of Representatives and the Senate will likely enable President Barack Obama to complete trade negotiations for the Trans Pacific Partnership, something the Democratic majority in the Senate was opposing.

Mr McConnell's hand has been strengthened by Republican wins against in seven states held by Democrats:

• West Virginia, where Shelley Moore Capito will be the first elected from her party in seven decades

• Arkansas, where Tom Cotton defeated incumbent Mark Pryor

• South Dakota, where Mike Rounds won against two opponents

• Colorado, where Cary Gardner beat sitting Senator Mark Udall

• Montana, where Steve Daines defeated Amanda Satines

• North Carolina, where Thom Tills gave the Republicans their 51st seat and a majority

• Iowa, where Joni Ernst beat her Democrat opponent, who is replacing a retiring senator.

While all states are not yet declared, the preliminary result will be the fourth time in less than a decade that voters have ousted a party from control of either the White House or Congress. It is also the first Republican majority in the Senate since 2007.

Another possible Republican gain is Louisiana, where a runoff election will be held on December 6 .

A recount has been ordered in Virginia, where incumbent Democrat Senator Mark Warner has a narrow lead.

Meanwhile, the Republicans are also picking up seats in the House of Representatives, where they already have a majority. The party is just 12 seats away from its post-war highest number of seats, 246, achieved in 1946.