NEW YORK - The woman who died after she was reportedly shoved in front of a moving subway train in New York City was the family housekeeper of the head of US private equity giant Blackstone, CNBC reported.

Its source was a New York Post report that cited a private Facebook post of CEO Stephen Schwarzman's son, Teddy.

CNBC said the New York City Police Department has identified the victim as 49-year-old Connie Watton of Queens.

"It's a very sad day for my family. One of the best people in the world, Connie Watton, was murdered yesterday," Teddy Schwarzman wrote in a Facebook post cited by the Post.

"Connie came to America legally from the Philippines when she was 18 years old, became an US citizen, and has had one job for her entire short life - working in my family's home as a housekeeper, friend and surrogate mother for the past thirty years."

The police said Melanie Liverpool-Turner and Watton were talking or arguing on the platform before Liverpool pushed Watton onto the tracks in front of a southbound No 1 train at the busy Times Square-42nd Street station around 1:20pm on Monday, US media reported.

At her arraignment in criminal court in Manhattan on Tuesday, Liverpool-Turner, 30, pleaded not guilty to a second-degree murder charge.