US Republican presidential candidate Donald Trump and his Democratic rival Vice-President Kamala Harris are effectively tied heading into the final weeks of the election, according to a national poll.

Trump is up one percentage point, 48 per cent to 47 per cent, over Harris, according to the survey of likely voters by The New York Times and Siena College released on Sunday (local time).

The difference is within the survey’s three-point margin of error, meaning a win for either candidate in the November 5 election is within reach.

When looking at all registered voters in the poll, Harris is at 46 per cent and Trump at 48 per cent – also within the margin of error.

Although the Trump campaign endured a relatively rocky stretch in the weeks after Democratic President Joe Biden dropped out of the race in July, the most recent polling indicates the core of his support base hasn’t gone anywhere.

The poll notably showed that voters felt they needed to learn more about Harris while their opinions on Trump were largely set.

In the survey, 28 per cent of likely voters said they needed more information about Harris. Only 9 per cent said the same about Trump.

A new national NYT/Siena poll finds Trump leading Harris 48% to 47% — the first time Trump’s led nationally in any major non-partisan national poll in ~3 weeks.

We’ll wait for more data to see if this is a blip or the start of a reversion, but NYT/Siena is an excellent pollster. pic.twitter.com/8VQK8RYCjB

— Adam Carlson (@admcrlsn) September 8, 2024

The poll indicates the presidential debate on US broadcaster ABC on Tuesday at 9pm (11am on Wednesday AEST) could be a crucial moment.

Harris will have the opportunity to give more detail of her planned policies as she spars with Trump over the course of 90 minutes.

The race is so close that even a marginal boost for either candidate would be significant.

Since Harris replaced Biden atop the Democratic ticket in the northern hemisphere summer, she has hit the campaign trail hard but has limited her unscripted appearances and kept interviews with the news media to a minimum.

“Look, it’s time to turn the page on the divisiveness,” Harris said during an outing in Pittsburgh at the weekend, as she took a break from preparing for the Trump debate.

“It’s time to bring our country together, chart a new way forward.”

CEASE & DESIST: I, together with many Attorneys and Legal Scholars, am watching the Sanctity of the 2024 Presidential Election very closely because I know, better than most, the rampant Cheating and Skullduggery that has taken place by the Democrats in the 2020 Presidential…

— Donald J. Trump Posts From His Truth Social (@TrumpDailyPosts) September 8, 2024

The key figures from the latest poll are similar to the last comparable NYT/Siena College survey, released in late July.

In that poll, Trump was also up one percentage point, a difference well within the margin of error.

Polls in the seven key swing states likely to determine the winner of the election have also consistently shown a razor-thin race.

-with AAP