Australian and Reds scrumhalf Will Genia's worst fears have been confirmed - he will be sidelined for six month.

Genia on Wednesday underwent surgery in Brisbane, where a full reconstruction was required of the ACL ligament in his right knee - an injury he sustained during last Saturday's 26-19 win by the Wallabies over the Springboks in a Rugby Championship Test in Perth.

 Although Wednesday's procedure went "well", it was confirmed Genia will now been sidelined for an estimated six months of rehabilitation before he can return to the field of play.

Genia has requested some quiet time in light of the surgery.

The Papua New Guinea-born 24-year-old, rated one of the finest scrumhalves in the world, has been replaced by Nick Phipps for the Wallabies' first match of the tournament against Argentina in the Gold Coast on Saturday.

This follows after the Wallabies confirmed their injury woes have worsened this week - with hooker Stephen Moore and utility back James O'Connor's return to fitness has been postponed.

Moore had been bracketed with Saia Fainga'a on the bench for the Test match against Argentina this weekend, but had to withdraw from the match-day squad after training on Tuesday as coach Robbie Deans is not willing to take any chances.

A return date for the injured O'Connor has also been put back and he will not now tour South Africa and Argentina with the team as originally planned.

The Melbourne Rebels flyhalf joined the Wallabies for training this week on the Gold Coast to ascertain the status of his rehabilitation but it was decided that he is not quite ready to be considered for the trip.

He will remain in Australia with a view to preparing for the upcoming year-end tour.