Xenophon said he has written to Australian Competition and Consumer Commission chairman Rod Sims, calling for an investigation into whether Apple had colluded with publishers and other resellers to raise the price of e-books in Australia.
The five publishing houses involved - Penguin, Hachette, Harper & Collins, Simon & Schuster and Macmillan - all settled with the US Government, but Apple decided to battle on alone.
US District Judge Denise Cote said the conspiracy had resulted in prices for some e-books rising to US$12.99 or $14.99, when Amazon had sold for $9.99.
Apple maintained Amazon was selling below cost, engaging in predatory pricing.
Apple is appealing against the decision.