Trump leads among Republican voters across US: Poll

 Republican presidential front- runner Donald Trump has secured a big lead among party voters nationwide, according to a latest US opinion poll.

Washington: Republican presidential front- runner Donald Trump has secured a big lead among party voters nationwide, according to a latest US opinion poll.

The real estate tycoon has support of 39 per cent of Republican voters, his highest total so far, and is followed by Senator Marco Rubio of Florida with 19 per cent, who is almost locked in a tie with Senator Ted Cruz of Texas with 18 per cent, said the Quinnipiac University National Poll.

Ohio Governor John Kasich has six per cent with former Florida Governor Jeb Bush and retired neurosurgeon Ben Carson at four per cent each. Nine per cent are undecided, the university said releasing the details of the poll.

In the Democratic race nationwide, former Secretary of State Hillary Clinton has 44 per cent, with Senator Bernie Sanders of Vermont at 42 per cent, and 11 per cent undecided, unchanged from February 5, it said.

"Reports of Donald Trump's imminent demise as a candidate are clearly and greatly exaggerated. Like a freight train barrelling through signals with his horn on full blast, Trump heads down the track towards a possible nomination," said Tim Malloy, assistant director of the Quinnipiac University Poll.

"Trump's raw numbers are formidable, but he trails the pack on some 'from the gut' character measurements. And the kind of bright spot that Jeb Bush supporters, few as they be, may grab hold of. The former Florida governor polls best in the pack on 'experience'," he said.

"Senator Bernie Sanders and Secretary Hillary Clinton are neck and neck. But while Bernie has the trust, Hillary has the experience. Two different measurements of two dissimilar candidates," Malloy added.

Trump has a good chance of winning the November presidential election, 77 per cent of Republican voters nationwide say, while 61 per cent favour Rubio and 60 per cent back Cruz.