One of Australia’s biggest hotel operators has made a deal to take over management and partial ownership of one of Hawaii’s biggest hotels.

Mantra Group has arranged to buy the commercial pieces of the 1,176-room Ala Moana Hotel from Honolulu-based Outrigger Enterprises Group for $52.5 million.

The Australian firm announced the pending purchase Tuesday, and said completion is expected at the end of July.

All of the lodging units in the hotel, which is adjacent to Ala Moana Center just beyond the Ewa end of Waikiki, are owned by individual investors, though most of them retain Outrigger to manage their units as hotel rentals. Mantra said 1,086 units in the hotel are under such management.

Mantra, which operates roughly 19,500 rooms at 125 properties in Australia, New Zealand and Indonesia, said the acquisition provides a platform to expand further into the Hawaii market.

“(The) Ala Moana acquisition is consistent with Mantra Group’s strategy to selectively expand its presence in key offshore regions via attractive and complementary new properties,” the company said in a presentation about the deal released on the Australian Stock Exchange.

The company also said it aims to raise occupancy at the hotel from its current 75 percent level, and increase revenue per room. The hotel is in good condition and underwent a refurbishment last year, Mantra added.

The property was converted from a traditional hotel into a condominium-hotel in 2005 by Miami-based luxury condo development firm Crescent Heights, which sold all of the rooms to individual buyers after acquiring the property from Japan-based Azabu USA for $85 million in 2004.

In 2007, Outrigger bought the front desk, parking, restaurant spaces, meeting and banquet rooms and most retail and office spaces from a Crescent Heights affiliate for about $14 million, according to property records, and took over management of the 36-story property with 425 employees.

Outrigger spokeswoman Nancy Daniels said Mantra is committed to retaining Outrigger’s employees at the Ala Moana Hotel, and that the sale was made to refine Outrigger’s core brand amid a strong real estate market.

“Outrigger believes that under the current market situation, this is the right time to proceed with a sale in order to strengthen Outrigger overall and over the long term,” Daniels said in an email.