The 34-year-old admitted the difficult decision was the right one for his family, but he would take away cherished memories of the fans at Warriors.
"After much consideration we feel, as a family, that this is the right time to return home to Australia, with my daughter starting high school and my son soon to start school," he said.
"I would like to thank Mike Ruddock and Cecil Duckworth for giving me the opportunity to come to Worcester and to Pat Sanderson and my team-mates for making me feel so welcome. It has been an enjoyable time in my career.
"I also need to make a special thank you to all the supporters. Their dedication to supporting the team has been absolutely magnificent. That is something I will take away from here as a memory of my time with Warriors.
"I am now fully committed to the rest of the season and looking forward to making sure Warriors fulfil their goals and make the top six in the Guinness Premiership. On a personal level, I'm looking to continuing to play some consistent rugby and a big role for the club."