Former NRL player Craig Field has appeared in court on Monday, charged over a fatal assault in far northern New South Wales.

Police say they responded to reports of an assault outside a hotel at Kingscliff around 9:15 on Sunday night and found a 50-year-old man lying unconscious on the ground.

CPR was performed before the man was taken to Tweed Heads Hospital where he died on Monday afternoon.

Field, 39, and Shaun Fathers, 41, were initially charged with assault occasioning grievous bodily harm but that charge was later upgraded to murder.

Both men appeared briefly in the Tweed Heads Local Court and were remanded in custody until the matter returns to court in Lismore next month.

Field, who made his debut with South Sydney as a 17-year old in 1990, was promoted to captain in 1994 before he was stripped of the role in 1995 for missing a training session.

He later joined the Manly club and was a member of the side which lost the Grand Final to the Newcastle Knights in 1997.

He also had a stint at Wests Tigers before heading to France to play for and coach the Pia Donkeys.

The veteran of more than 100 first-grade rugby league games currently works as an electrician in Kingscliff.