Bernie Sanders takes early lead in New Hampshire primary as Biden lags behind   

Vermont Senator Bernie Sanders took an early lead in New Hampshire's Democratic presidential primary on Tuesday.

Sanders was closely followed by Pete Buttigieg and US Senator Amy Klobuchar.

With 25 per cent of precincts reporting, Sanders led with 26.1 per cent and Pete Buttigieg, the moderate former mayor of South Bend, Indiana, had 24.3 per cent. Senator Amy Klobuchar, looking for a breakthrough after a strong debate performance on Friday, was in third with 19.8 per cent.

Former vice president and initial front-runner Joe Biden trailed badly in distant fifth place in the second contest to find a nominee to face President Donald Trump on November 3, 2020.

Results began rolling in quickly after polls closed, and Democrats in New Hampshire were confident they would have smoother sailing than in Iowa, where embarrassing technical problems and inconsistencies delayed vote-counting and the release of results for days.

Buttigieg narrowly beat Sanders in Iowa, but both campaigns have asked for a partial recanvass of the results.

Democratic voters in New Hampshire chose a candidate from a ballot with 33 names, including candidates who dropped out weeks ago. But it did not include former New York Mayor Michael Bloomberg, a billionaire who is not competing in any states before the 14 Super Tuesday primaries on March 3, reported news agency Reuters.

Sanders had taken a lead in recent opinion polls in New Hampshire despite a barrage of criticism from rivals who warned his far-left views would lead the party to defeat against Trump.