Trump, wearing a black face mask and accompanied by first lady Melania Trump, stood near the casket at the marble court building on Thursday amid chants of "Vote him out".

The moment highlighted the public flashpoint that Ginsburg's death has become ahead of the November 3 presidential election.

The Republican president, who has already installed two top court picks since taking office in 2017, has said he would unveil his latest choice on Saturday, a week after the 87-year-old justice died on September 18.

His decision to move quickly on a replacement just six weeks before the election has drawn sharp battle lines between Republicans and Democrats, and reshaped the race for the White House as Trump seeks re-election during a coronavirus pandemic that has killed more than 200,000 people in the United States and devastated the economy.

Ginsburg, appointed by Democratic President Bill Clinton in 1993, was an icon for liberals, especially as the court grew increasingly conservative.

Her death has sparked a renewed push by Democrats to get people to the polls in November and an outpouring of campaign donations.

Trump dismissed the protests.

"I think that was just a political chant. We could hardly hear it from where we were," he told reporters later in the day.

White House spokeswoman Kayleigh McEnany called the chants "appalling and disrespectful".

Before his election to president in 2016, Ginsburg criticised him publicly, calling him "a faker" in one interview.

Trump responded by writing that Ginsburg's "mind is shot" on Twitter. She later apologised, saying she regretted the "ill-advised" comments.

The president has maintained a respectful demeanour in his remarks about Ginsburg since her death, but he has drawn criticism from Democrats for not honouring her wish, reportedly dictated in a statement to her granddaughter, that she be replaced by the next president.

Australian Associated Press