According to the Foxtel Guide, Season 4 will be premiere tomorrow in Australia. The episode is listed as "The Fairy Hunters", so we can presume that this will be RAI English and not 4Kids dub, which Boomerang Australia aired previously.
For those in Australia, the episode will premiere at 4:05 PM, with repeats at 10:05 PM and 9 AM. Boomerang is channel 715.
(Thank you Winx-Fairies for the picture, click it to enlarge.)