According to next-gen.biz, GTA IV was knocked off the top spot after only one week at the summit.
However, the sandbox title did claim second and third on the chart, followed by two further Wii games, Wii Play and Mario Kart Wii.
The full Australia top ten for week ended May 11th reads:
01. Wii Fit (Wii)
02. Grand Theft Auto IV (360)
03. Grand Theft Auto IV (PS3)
04. Wii Play (Wii)
05. Mario Kart Wii (Wii)
06. More Brain Training (DS)
07. Brain Training (DS)
08. Time Crisis 4 (PS3)
09. Mario & Sonic at the Olympic Games (Wii)
10. Gran Turismo 5 Prologue (PS3)