Voters are now able to cast their ballot in Minnesota, South Dakota, Wyoming and Virginia.

Hundreds of people were queuing at a polling station in Fairfax, Virginia, early on Friday, according to CNN.

Local officials told the broadcaster they had never seen so many voters turn out on the first day.

Most US states and the country's capital Washington DC allow no-excuse early voting and people can send in their ballots early by post in many states.

North Carolina was the first state to start mailing ballots to voters two weeks ago.

Early voting has increased in recent election cycles as part of an effort to streamline the process, and has gained momentum amid fears about the coronavirus spreading as people gather at polling stations during the pandemic.

A poll released this week by the Washington Post and ABC News indicated that 44 per cent of Wisconsinites and 39 per cent of Minnesotans planned to vote ahead of election day.

Experts expect a massive increase in postal voting this year.

US President Donald Trump has argued repeatedly that mail-in ballots are vulnerable to voter fraud.

Trump and Democratic presidential nominee Joe Biden are to hold duelling campaign events in the mid-western state of Minnesota on Friday.

Australian Associated Press