Former US President Donald Trump won the Republican caucuses in Nevada on Thursday, further solidifying his lead in the party's presidential nomination race.

With 80 percent of the ballots counted, Trump won 99.2 percent of the votes.

Trump's victory was effectively guaranteed because his biggest rival, former US Ambassador to the United Nations Nikki Haley, did not participate in the contest.

While Nevada held a primary on Tuesday, the state's Republican Party views the caucuses as its official nomination process. Haley ran in the primary, which did not allocate any delegates.

Trump has won all three Republican contests so far, beginning with Iowa and followed by New Hampshire. He now has 62 delegates, far outnumbering Haley's 17.

In a speech at a rally, the former president thanked the "great people of Nevada" and said, "We win this state, we easily win the election in November. We have to win the election."

The next Republican contest is a primary in South Carolina on February 24.

Haley has been focusing her campaign efforts on this state, where she previously served as governor. If she fails to achieve a notable result there, pressure for her to drop out of the race will intensify.