
Federer, who will be bidding for his 13th Grand Slam title from January 14 at Melbourne Park, will fine-tune at the eight-man special event at Kooyong club traditionally used by the elite to prepare for the season's first major.
The Swiss and Roddick will be joined by Russian Marat Safin and Fernando Gonzalez of Chile, a former Australian Open winner and finalist respectively.
Also competing at the January 9-12 round-robin event: Tommy Haas, Ivan Ljubicic and British tyro Andy Murray.
One spot remains open for organisers to award a wild card at the last moment in the run-up to the Open.
DPA