Speaker Sir Lindsay Hoyle sent out the new rules to MPs stating that parliamentary staff would be “required” to use face coverings until the summer recess.
The guidance added MPs would only be encouraged to wear masks.
A section titled “Outside the Chamber” states: “Until 22 July, Members will be encouraged to continue wearing face coverings, and all others on the estate will be required to wear them while moving around the estate or entering venues.
“It will also mean that until the rise of the House the overall capacity of the estate will remain limited.”
A spokeswoman for Sir Hoyle told the Standard the guidance applies only up to July 22.
She added: “We have no employment or contractual relationship with Members which would enable us to mandate the wearing of masks. We therefore encourage Members to support us in keeping the estate safe.”
One staff member working in the palace told the Huffington Post: “It’s literally one rule for them...”
Transport companies have the power to turn away customers who refuse to cover their noses and mouths even when the legal requirement is lifted on July 19.
On Monday, Prime Minister Boris Johnson said “we expect and recommend” that people continue to wear face coverings in “crowded and enclosed spaces … such as on public transport”.
Cross-Channel train firm Eurostar and airlines such as British Airways, easyJet and Ryanair will continue to require passengers to wear face coverings from July 19.
But train industry body the Rail Delivery Group (RDG) announced that all domestic train operators, such as Avanti West Coast, TransPennine Express and Southeastern, will not go that far.