ASIO's new lakeside office building in Canberra will have cost taxpayers more than $700 million by the time it is operational in September.
Another $71 million was allocated to the intelligence agency in this month's budget ''primarily relating to the new central headquarters''.
As the political row raged this week over allegations that Chinese computer hackers stole vital plans and blueprints of the building, ASIO officials confirmed that the money would be used for ''asset replacement'' to coincide with the move into the new offices.
A spokesman for the agency said the $71 million was on top of the $633 million spent on construction of the massive office building, which is already $170 million over budget and nearly a year behind schedule.
''The figure quoted [in the budget papers] relates to routine asset replacement timed to coincide with ASIO's move into the new building,'' the spokesman said.
''The expenditure is unrelated to building construction costs.''
The money is believed to be for equipment to be used in the building when 2000 of the agency's staff move in in September but ASIO would not provide details on Wednesday.
''For security reasons ASIO does not publicly disclose details of its asset replacement program,'' the spokesman said.
''ASIO's financial records and systems, including asset management, are subject to annual audit by the Australian National Audit Office.''
According to ASIO's budget portfolio statement the new building will improve the agency's ''organisational connectedness'' but conceded it might be difficult to manage the monster move into the lakeside offices while maintaining its complex operations.