WASHINGTON (REUTERS) - US Supreme Court Justice Ruth Bader Ginsburg is resting comfortably after undergoing a non-surgical medical procedure on a bile duct stent on Wednesday (July 29) at a New York City hospital, the court said.

Ginsburg, at 87 the oldest member of the Supreme Court and its senior liberal justice, expects to be released from Memorial Sloan Kettering Cancer Centre by the end of the week after doctors revised a bile duct stent that was originally placed in August 2019, the court said in a statement.

"According to her doctors, stent revisions are common occurrences and the procedure, performed using endoscopy and medical imaging guidance, was done to minimise the risk of future infection," it said.

Ginsburg, who has had a series of health issues, said two weeks ago she was receiving chemotherapy treatment for a recurrence of cancer after a biopsy revealed lesions on her liver.

Ginsburg was treated for pancreatic cancer in 2019 and 2009, for lung cancer in 2018 and colon cancer in 1999.

Ginsburg's health is closely watched because a Supreme Court vacancy could give Republican President Donald Trump the opportunity to appoint a third justice to the nine-member court and move it further to the right.

The court currently has a 5-4 conservative majority including two justices appointed by Trump - Brett Kavanaugh in 2018 and Neil Gorsuch in 2017.