The department has begun a three-month study into alternative accommodation and it is understood that three frontrunners have emerged: Canary Wharf, an office at Bankside, across the Thames from St Paul's cathedral, and East Croydon in Surrey.
The source said: "Office space on the South Bank would be the preferred choice because of its more central location, but obviously space in Docklands would be better than travelling to Croydon."
According to the source, government officials met key figures at Canary Wharf last week to discuss potential sites in its Docklands estate.
Government officials also plan to hold talks with developer Stanhope over letting space at a planned development next to East Croydon station.
If the department does choose Croydon, the least expensive option, it would be a boost for Stanhope's hopes of getting the scheme off the ground.
The developer teamed up with investment bank Schroders in February to buy a derelict site for a £200m complex of offices, flats and shops.
A DTI decision to switch staff to Croydon might help Stanhope obtain planning consent for the 186,000 m2 scheme. It is encountering difficulties because Croydon council has other plans for the site – it wants to bolster its claim for city status by building a sports and music stadium.
A DTI spokesperson confirmed that a three-month property review was under way but refused to be drawn on potential sites for a relocation.
It is understood that key staff will remain in the headquarters, including those working for Brian Wilson, the construction minister.