Las Vegas: Donald Trump won Tuesday's Republican presidential caucuses in Nevada, US networks projected, giving the billionaire businessman his third straight win in the race for the White House.

CNN and Fox News projected that Trump had won 42 percent of the vote in the Silver State, with Florida Senator Marco Rubio coming in second with 25 per cent of the vote.

Texas Senator Ted Cruz came in third with 21 per cent of the vote, according to the projections.

The remaining two candidates, retired neurosurgeon Ben Carson and Ohio Governor John Kasich, came in last at eight and four percent respectively.

This was Trump's third victory, following wins in New Hampshire and South Carolina.