Expats drink it all in at US election watch parties

US election watchers have gathered at Australian venues where many enjoy a beer as the world's most powerful democracy changes shape.

Supporters of Democrat Kamala Harris were holding on to hope, while some Donald Trump backers insist only a conspiracy can stop the former Republican president's return to the White House.

As the first polls closed on the US east coast, the crowd started to swell inside one Sydney watering hole in the late morning.

Maggie Donahue was an earlier arrival and scored a prime spot near a screen showing CNN.

She came to watch the election coverage "with other Americans who are equally as concerned as I am about it".

"I am very cautiously believing, hoping, that Kamala will win by a narrow margin," she told AAP.

"It'll be close ... but I have a small sliver of hope."

Ms Donahue worked for the US government over six years spanning the Trump and Biden administrations.

"I was in a federal government building the day of January 6, 2021," she said, referring to the date a mob of Trump supporters stormed the US Capitol.

"We were not sure if they were going to come for us next, but mostly it was deep concern for my country ... and the people, friends and colleagues who worked on the hill."

Democrats Abroad Australia committee member Amy Saha said she was quietly "but absolutely optimistic".

"It really does feel like we, Harris-Walz, have momentum," she said.

"America is really coming into election day aware of how dark and divisive the Trump campaign has been and Democrats definitely feel united."

Ms Saha wore a star-spangled top hat and attendees could take photos with a cardboard cut-out of Ms Harris at the Sydney event.

The pub served American-brand beers and food including bagels and Buffalo wings, while the steak carried a side of "Freedom fries".

Similar events were due to be held in other major cities, including a Democrats Abroad watch party in Canberra and an American Chamber of Commerce-organised event in Melbourne.

Sharing a bucket of Coors in the back of the Sydney pub, Ben, who declined to give his last name, said the beers were "alright" but not the main point of attending.

"We're coming here to support our president ... it's a Trump victory, unless they rig it of course," he said.

Sitting across the table, Dean Thorby said the Republican candidate's vacillation on abortion might cost him votes from women, but he still expected a Trump victory.

"Just because he's way more populist, she's way more of a drone," he said.

"You just have to look at the economy over the past four years and how everything has gone to s***," Ben interjected.

The pair, both Australians, agreed the outcome would have significant consequences for local politics.