Colonial First State Property is in exclusive talks with a potential buyer to sell the Aurora Place office tower in Sydney by mid December.

The two parties are in the due diligence period of negotiations, Angus McNaughton, head of wholesale property and strategy at Colonial, said in a telephone interview from Sydney today. He declined to comment further.

South Korea’s National Pension Service is preparing to buy the 44-story tower for about A$685 million, the Australian newspaper reported today. The tower, overlooking Sydney Harbour, is owned by an unlisted wholesale property fund managed by Colonial First State, the Australian said.

The purchase would be the biggest office sale in almost two years, the Australia said.