The former girlfriend of an NRL star is believed to have been found dead at the age of 25.

Brittany Hura was in a volatile relationship with Bryce Cartwright, of the Penrith Panthers, before the couple split acrimoniously after six years.

She then posted a revenge porn video threatening to kill the player and police took out an AVO to keep her from going within 250 metres of him.

Friends and family posted tributes on Facebook this afternoon, reported the Daily Mail.

"RIP Brinney Hura, condolences to all her whanau. Too song and so young… rest easy gurl," one tribute read.

A NSW Police spokeswoman confirmed the body of a 25-year-old woman had been found in Constitution Hill, in western Sydney, on Monday night.

A crime scene was established, enquiries are under way and a report is being prepared for the coroner, the spokeswoman said.

A post-mortem will be conducted to determine the cause of death.