Marriott Asia-Pacific boss Raj Menon said he would not be surprised if the new W Sydney was fully booked over the New Year holidays, as the huge luxury hotel overlooking Darling Harbour finally opened its doors on Thursday after years of delays.

Mr Menon, who joined Marriott International chairman David Marriott and 29-year-old Wayne Wang, the owner of the hotel property, in cutting the ribbon on the eye-catching, curved $1 billion property, said a 50 per cent occupancy rate was anticipated during the first month of operation.