Parramatta Eels have terminated the contract of Tony Williams, effective immediately, and heavily sanctioned centre Nathan Davis after they each tested positive for a second time for "illicit and hazardous drugs".

Williams has also been suspended for 12 matches meaning another NRL club is highly unlikely to get another contract in 2019.

The Eels released a statement in which the club said it would "continue to offer welfare assistance and support to both players".

Williams returned to the Eels in 2018 after his one-season stint at Cronulla was cut short by a torn ACL.

The towering forward, who will turn 30 in December, had represented Australia in five Tests and Samoa in another five while also playing three matches for NSW during previous stints with Manly and Canterbury.

Eels centre Nathan Davis. ©NRL Photos