The House of Commons is spending £1,500 a week on vermin control after Westminster Palace bosses received a series of complaints.
Seagulls and pigeons are noted to be scavenging for food and mice and rats are seen running around the halls.
The figures come from the Parliament website and also mention moths eating away at historically significant tapestries.
A report examining the damage said: “The Parliamentary Estate is made up of a large number of buildings of various ages, covering approximately 258,000 square metres close to the River Thames.
"It is therefore vulnerable to populations of animals which can cause significant damage to the fabric of the buildings and health and safety issues.
"Controlling these pests is a major undertaking, and is conducted by a full-time pest control technician provided as part of the Houses’ pest control contract and a contract for bird control."
A report into the pest control problem revealed there are 1,629 mouse and 128 rat bait stations as well as 729 moth and 92 fly control devices.
Birds of prey are used on the outside of the building to try to keep pigeons and seagulls at bay.
The document justified the spendings by saying that "other bird control measures would be unsightly on a World Heritage Site".
One complaint read: “We were somewhat concerned when visiting the cafe next to the gift shop when my wife was alarmed to see a mouse running across the floor and under a cabinet.
“She mentioned this to the serving assistant who seemed unconcerned, passing it off as a regular occurrence.
"Having been involved in the catering industry, we were concerned about the obvious food hygiene issues where food is being served.
Another visitor said they were disgusted by pigeons and seagulls swooping down onto the terrace outside the Commons to grab food from plates.
Members of staff are encouraged to report all sightings of pests in and around the buildings.
