SINGAPORE, Aug 29 (Reuters) - U.S. gaming giant Las Vegas Sands expects its Singapore casino resort to cost as much as $5 billion, nearly 40 percent up from its original projection, Singapore newspapers reported on Wednesday.

Sands Chief Operating Officer William Weidner told Singapore reporters at a briefing in Macau that rising construction costs, coupled with design refinements, had pushed up the overall cost of the resort by between 20 to 40 percent.

"We are struggling quite frankly to stay within budget," the Straits Times quoted Weidner as saying at the opening of Sands' Venetian-themed casino in the Chinese enclave of Macau.

Weidner said the Singapore project, which is located along the city state's downtown waterfront, is on schedule to open in late 2009 and that a third of the required funding had been secured.

Sands won an international bid for the Singapore casino -- the first of two planned in the city state -- with a proposal for a $3.6 million complex that would include gaming, hotel and convention facilities.

Weidner said the firm was in discussions with the Singapore government on rising construction costs.