WASHINGTON (AFP) - Republican presidential candidate Donald Trump landed just ahead of Democrat Hillary Clinton in a new national poll released on Tuesday (Sept 6), which showed the real-estate mogul chiseling away at his opponent's former lead.

Mr Trump beat Mrs Clinton 45 to 43 per cent in the new CNN/ORC Poll, which showed stark divisions in the way different demographics plan to cast their ballots.

Mrs Clinton has mostly maintained an edge over Mr Trump in recent national polls. She has dramatically deeper ground operations in swing states and trounced Mr Trump in August fundraising.

But the Republican flagbearer's unorthodox White House bid, including his campaign's apparent imperviousness to criticism about his harsh rhetoric, assures a tight contest leading up to Nov 8.

The near tie in the latest CNN/ORC results came in sharp contrast to Mrs Clinton's eight-point lead among registered voters in its early August poll following the Democratic Convention.

According to CNN, huge gaps exist in voting preference based on gender, age, race, education and partisanship.

Women prefer Mrs Clinton 53 to 38 per cent, while men favor Mr Trump 54 to 32 per cent, it said.

Voters younger than 45 give Mrs Clinton an edge (54 per cent to 29 per cent for Mr Trump), while non-whites favour Clinton by almost four-to-one, poll results showed.

Enthusiasm for the overall 2016 campaign remains comparatively low. Almost half of voters say they are less enthusiastic about voting this year than in previous elections, with just 42 per cent reporting that they're more excited.

This marks the first time since 2000 that a significantly larger share of voters say they are less excited, CNN polling results indicate.

The CNN/ORC poll was conducted from Sept 1 to Sept 4 by telephone among a random sample of 1,001 adults. It included results from 886 registered voters and 786 likely voters. For results among registered or likely voters, the margin of error is plus or minus 3.5 percentage points.