Donald Trump's pick for the Supreme Court dodged questions on Wednesday over whether the US president had the power to pardon himself.

Lawmakers grilled Amy Coney Barrett for a third day during a Senate hearing in which the 48-year-old federal judge was also quizzed on abortion, racial inequality and gun rights.

Republicans want to fast-track the conservative jurist's appointment to the highest court in the United States.

Democrats argue the winner of the forthcoming November 3 election should decide who replaces the late Ruth Bader Ginsburg, a liberal firebrand who passed away last month.

Read more: Who is US Supreme Court nominee Amy Coney Barrett?

Skirting presidential pardons issue

Senators asked Barrett if Trump could use his presidential powers to grant himself a pardon in the event of any legal woes.

She said that the question "may or may not arise, but it's one that calls for legal analysis," adding that in the US "no-one is above the law."

Barrett also rebuffed queries about whether Trump's private businesses receiving money from foreign sources violated the Constitution.

Conservatives hailed the Catholic mother of seven, arguing she would stand firm on stricter abortion rules.

"This is the first time in American history that we've nominated a woman who is unashamedly pro-life and embraces her faith without apology," said Lindsay Graham, the chair of the judiciary committee and a senator from South Carolina.

Barrett says she will keep faith separate from the legal issues that come before her.

Read more: Opinion: Donald Trump opts for a lurch to the right in the Supreme Court

Cementing conservative dominance

If she is successfully confirmed, Barrett would give the Supreme Court a 6-3 conservative majority. Appointments to the court are for life.

A key hearing on health care is set to take place in the second week of November.

Democrats worry Barrett could step in and decide to strip back Barack Obama's signature healthcare reform, known as Obamacare.

jf/dr (AP, dpa)