Democracy is sometimes messy and requires a little patience, Democratic presidential candidate Joe Biden has said as the counting of votes for the US election is taking longer than usual.

Biden also urged Americans to stay calm and wait patiently while every vote is being counted. Biden needs just six electoral college votes to reach the magic figure of 270 and win the race to the White House, while President Donald Trump has 214 electoral college votes.

"In America, the vote is sacred. It's how the people of this nation express their will. And it is the will of the voters, no one — and not anything else — that chooses the President of the United States. So, each ballot must be counted and that's what is going on now. And that's how it should be,” Biden said in his address to the media in Delaware on Thursday.

"Democracy is sometimes messy, so sometimes it requires a little patience. But that patience has been rewarded now for more than 240 years with a system of governance that has been the envy of the world. We continue to feel very good about where things stand,” he said.

In the US election, voters decide state-level contests rather than a single, national one. Each US state gets a certain number of Electoral College votes partly based on the size of the population, with a total of 538 up for grabs.

Biden, accompanied by his running mate Senator Kamala Harris, said he has no doubt that when the count is finished, they will be the winners.

"So, I ask people to stay calm. The process is working. The count is being completed. And we will know soon,” he said.

Earlier in the day, Biden and Harris had full briefings on the COVID-19 pandemic and the economic crisis facing the nation. "We're reminded again of the severity of this pandemic. Cases are on the rise nationwide and we are nearing 240,000 deaths due to COVID,” he said.

“My heart goes out to each and every family that has lost a loved one to this terrible disease," Biden said.