A statement from Buckingham Palace said the 95-year-old monarch “will continue with light duties”.
It was confirmed on Sunday that the Queen had tested positive for Covid and was experiencing mild symptoms.
So far it is still planned that she will attend a diplomatic reception next week.
The announcement that the Queen had caught Covid had been accompanied by a reassurance that she was well enough to carry on working from Windsor Castle.
It had been seen as a business as usual message, to avoid any alarm about her health.
On Sunday she signed off a message of congratulations to the GB Winter Olympics curling teams and on Monday sent a message of condolence to Brazil after fatal flooding.
But this latest update says that the Queen has decided not carry out any engagements on Tuesday – although she will continue with other duties, which is likely to be working on state papers.
A number of people have also tested positive in what appears to be a Covid outbreak at Windsor Castle where the Queen lives, it is understood.
Both Prince Charles and Camilla, Duchess of Cornwall have recently had Covid.