Minister of State for the Armed Forces Adam Ingram unveiled a plaque at DLO Andover's north site, confirming its status as the largest employer in town.
The new development has been open for nearly a year but had its official opening postponed because of the recent Iraq campaign.
Mr Ingram paid tribute to the logistics staff at the site and said many of them played a critical role in the Iraq war by ensuring equipment and supplies got to the troops.
He said: "The people who work here in the logistics chain are often the unsung heroes. I am pleasantly surprised at how modern and light this building is. The architects and designers have done their level best to create a friendly working environment."
The new 34-acre site will house around 800 staff, a warrant officers' and sergeants' mess, a day nursery and a helicopter landing pad.
The Mayor of Test Valley Pat West said: "This opening reinforces the strong working relationship between Test Valley Borough Council and the DLO. I think it is a magnificent building."
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