Sites gifted to the Stormont Executive by the Ministry of Defence cost more than £1.4 million a year to manage, it has been revealed.
Security, maintenance and other annual expenses totalling £1,428,442 have been attributed to land at six locations which was handed over for economic and social regeneration projects.
The information was released by the Office of First and Deputy First Minister (OFMDFM) in response to a written question by DUP MP Gregory Campbell.
The East Londonderry representative claimed the higher than expected costs emphasised a need to properly utilise former military bases.
"There needs to be a step up in terms of what each of the sites could be used for, so that the costs are reduced," Mr Campbell said. "The public purse simply cannot be expected to stand this forever."
Almost half a million pounds a year was spent maintaining the disused Shackleton army base in Ballykelly, Co Londonderry, OFMDFM said. The site has been earmarked as a new headquarters for 800 staff from the Department of Rural Development, with work due to start next year.
Mr Campbell added: "The costs are for the site to remain empty. That just indicates the correctness with the decision to move some departments to Shackleton. These figures simply ensure that we have got to get utilisation of these sites - and make sure it is the best utilisation."
Annual maintenance costs for Ebrington Barracks which is also in Derry were estimated at £235,112 by OFMDFM. The site, which was transferred in December 2003, is managed by Ilex Urban Regeneration Company Ltd on behalf of the Executive. The historic parading ground has been redeveloped into a public space.
Mr Campbell said he hoped a decision by the Royal Ulster Agricultural Society (RUAS) to relocate its headquarters from the King's Hall in Belfast to a 55-acre site at the former Maze prison would help cut the yearly £170,290 bill.
Meanwhile, keeping St Patrick's former army base in Ballymena, Co Antrim, has cost £270,596 a year. The former Royal Irish Rangers base which contains 47 former MoD homes was handed to OFMDFM in 2004 and has been earmarked for social housing. However, the project has been dogged by delay.