Staniforth joined London Irish from the New South Wales Waratahs

Director of rugby Brian Smith said: "He and his family are moving to address a pressing family health matter."

Staniforth is expected to continue his career with Western Force, the new Super 14 franchise in Perth.

Staniforth joined London Irish in July 2004 and made 34 appearances, scoring 13 tries. He was the club's player of the season in 2004-05.

"I have enjoyed playing with the boys and the supporters have been fantastic," he said.