The Beverly Hilton Hotel, the site of a stalled $500 million development, was put up for sale Monday by owner Beny Alagem.

The decision was triggered by several unsolicited offers for the historic hotel, where four years ago Alagem proposed adding two condo towers and a Waldorf Astoria hotel.

His proposal was fiercely opposed by some Beverly Hills residents, who forced a referendum. The project was narrowly approved in December 2008 but by that time the real estate market had already started its steep decline.

Also playing a role in the decision was the $148 million sale last month of 9900 Wilshire Blvd., the site of the closed Robinsons-May department store, where another large condominium development has stalled.

A Hong Kong and Singapore investor group bought the Robinsons-May site, where British developers Candy & Candy Inc. had proposed an upscale condo complex designed by Getty Center architect Richard Meier. The developers paid $500 million for the property in 2007 but later lost it in foreclosure. The new owners have said they plan to redevelop the property based on Meier’s plans.

“After receiving serious proposals over the past several months, Mr. Alagem is at a turning point and needs to decide whether to initiate the proposed development of the property,” said Rob Stiles, executive vice president and principal, head of the western region for Cushman & Wakefield Sonnenblick Goldman, which is listing the property.

“Given the proposals and Mr. Alagem’s desire to begin development within the next 12 to 24 months, now is the right time to explore the alternative of a sale,” Stiles said.

Alagem, who co-founded computer maker Packard Bell, bought the hotel for $130 million in 2003 from entertainer Merv Griffin.