Speight, 28, returns to the squad after playing for Australia's rugby sevens side at the Rio Olympics where they reached the quarter-finals, while Arnold has overcome an elbow injury to feature and will look to build on strong showings in his two tests to date.
Fiji-born Sefa Naivalu of Melbourne Rebels is yet to complete his nationality switch, but will train with the squad before becoming eligible on September 18th and is one of four uncapped inclusions alongside Kyle Godwin, Lopeti Timani and Tom Robertson.
