Apple is vehemently denying that it colluded with other publishers over the price of e-books, as the Department of Justice (DOJ) claims. The DOJ filed suit against Apple and five other publishers on Wednesday, saying the companies partook in an “illegal conspiracy” to fix the prices of e-books–a violation of antitrust laws.

“The DOJ’s accusation of collusion against Apple is simply not true,” Apple said in a statement, which it first issued to online publication All Things D yesterday.

Apple and two of the other named defendants–MacMillan and Penguin–plan to fight the claims. The other three publishers charged–Hachette, HarperCollins and Simon & Schuster–have agreed to a proposed settlement.

In 2009, when publishing executives began meeting with Apple to discuss competition issues, Amazon’s e-book pricing was part of the talks. According to Attorney General Eric Holder that amounted to “part of a conspiracty to raise, fix and stabilize retail prices.”

Apple denies those allegations. “The launch of the iBookstore in 2010 fostered innovation and competition, breaking Amazon’s monopolistic grip on the publishing industry,” the company said in its statement.

Australia may be next in line to file suit against Apple over e-book pricing. Although the Australian Competition and Consumer Commission (ACCC) wouldn’t confirm it planned to pursue the collusion charge against Apple when it talked to the country’s consumer watchdog, The Australian Financial Review, it did tell the group, “Competition concerns may arise where traders seek to restrict the discounting of products by way of restrictive arrangements with suppliers.”

Last month, Apple settled a suit with the ACCC over claims the company made about its iPads.