Cross is a hugely experienced player with strength and power and joins the Warriors from his recent release from Leeds Rhinos.
Warriors coach Michael Maguire said: “Ben is a good addition to our squad and will add extra competition for places. He is a great character and a player I know well from my time in the NRL. He is looking forward to another chance to play in the Super League.”
Cross added: “This is a wonderful opportunity for me and I am really looking forward to working with Michael again. It is a huge honour to be joining the current champions.”