The Belfast city centre home of Invest NI and two other public sector bodies has gone on sale with an asking price of £40m plus.
Bedford Street Developments - a joint venture of Cookstown-based developer McAleer and Rushe and Dunloe Ewart - is putting part of its Bedford Square portfolio on the market.
The properties on sale are home to Invest NI and the Linum Chambers Building, which in turn houses the Public Prosecution Service and the Northern Ireland Law Commission. However, the sale will not affect the tenants.
Commercial property agents Osborne King and ASM Chartered Accountants have been appointed to sell the 100,000 sq ft of office accommodation and 71 basement car parking spaces.
Stephen Surphlis of Bedford Street Developments said: "This is part of our planned strategy aimed at exiting certain investment properties within our portfolio."
The offices were built by McAleer and Rushe under a public private partnership in 2005.
Robert Ditty of Osborne King said the building was a "landmark" of Belfast's business district. "We anticipate keen interest from institutional and overseas investors. This is a positive step in terms of attracting inward investment to the Northern Ireland economy.
"As a showcase example of a public private partnership working successfully since November 2005 and an office occupied by Government, we anticipate achieving a price in excess of £40m."
Irish developer Liam Carroll is a former director of Bedford Street Developments. A spokesman for McAleer and Rushe said Mr Carroll had no involvement in the Bedford Square development.