A Wal-Mart employee in New York state's Long Island died when a throng of shoppers surged into the store and physically broke down the doors.

The 34-year-old man was at the entrance of the Valley Stream Wal-Mart store when it opened at 5am (10am Irish time) and was knocked to the ground.

The exact cause of death was still to be determined by a medical examiner.

Four shoppers, including a 28-year-old pregnant woman, were also taken to local hospitals for injuries sustained in the incident.

The Friday after America's Thanksgiving holiday is known as Black Friday and marks what is traditionally the busiest retail day of the year, kicking off the Christmas shopping season.

US stores across the country opened in the early hours of today to offer discounts to consumers hit by a contracting economy.

Hundreds of shoppers waited on line before dawn at some locations to secure deals on holiday gifts.

Representatives at Wal-Mart, the world's largest retailer, were not immediately available for comment.