(Adds details on regulator's concerns and Aurizon divestiture, its share move and reaction)
July 19 (Reuters) - Australia's competition regulator sought a court injunction on Thursday against rail operator Pacific National's proposed acquisition of Aurizon Holdings Ltd's AZJ.AX Acacia Ridge Terminal and Queensland intermodal business.
The Australian Competition and Consumer Commission (ACCC) said its application with the federal court was also seeking to prevent Aurizon from closing the intermodal business, as well as pecuniary penalties against the firms.
It alleged the deal, along with the appointment of Pacific National to operate the Acacia Ridge Terminal, would have the effect of "creating a monopoly on that route".
In mid-March, Aurizon said it was committed to completing the freight business's sale despite the ACCC's concerns, and would close the business if the deal did not go through, costing up to 350 jobs. deal would have been worth A$225 million ($166.6 million), as it was not completed within six months of the original announcement in August 2017.
Aurizon in a statement said the ACCC's decisions negatively affected its commercial interests and it would defend the proceedings started by the regulator.
Aurizon shares fell 2.3 percent to trade at A$4.27 at 0017 GMT, compared to a flat overall market .AXJO . ($1 = 1.3508 Australian dollars)