According to US media, Donald Trump has scored a crucial victory in the presidential nominating contest in his home state of New York.

CNN said Trump won 68.6 percent of the vote in the Republican primary on Tuesday. The victory pushes him closer to the 1,237 delegates needed to win the party's nomination.

Democratic front-runner Hillary Clinton also sought a big victory in New York, which she once represented in the U.S. Senate. But there's no immediate projections in the Democratic primary at the close of polls, signalling a tighter race.