"Government ministers must come to the House of Commons to explain what happened, how it was allowed to happen and what they are doing about it."
Nineteen 9mm pistols, 13 shotguns and three starter pistols are missing from the 14 Regiment Royal Artillery base at Larkhill, Wiltshire.
The theft was discovered at about 0730BST on Wednesday, during a check on one of the base's armouries.
In a brief statement, Superintendent Bill Hammersley, area commander for the MoD Police, said: "A major investigation is currently being undertaken.
"The MoD Police would like to appeal to anyone who may have knowledge of this incident, or may know the identities of those involved."
Shadow defence secretary Iain Duncan Smith, said: "This is a matter of serious concern, as these weapons in the wrong hands could be lethal.
"Government ministers must come to the House of Commons to explain what
happened, how it was allowed to happen and what they are doing about it."
The MoD police said cars entering and leaving the base on Salisbury Plain would be searched until the weapons - which included guns privately owned by members of the base - were found.
The spokesman said he could not say whether there had been a break-in at Larkhill Royal School of Artillery, but confirmed that no ammunition had gone missing.
A spokesman for the MoD police said the weapons were likely to have been removed overnight.
The disappearance of the weapons follows a recent series of security blunders. Last month, MI5 reviewed security procedures after a laptop computer containing classified information on Northern Ireland was snatched from an officer.
Four days later it was reported that another laptop - this time belonging to an MI6 officer - had been mislaid in a London bar. It was recovered after an investigation.