"The Queen continues to make a good recovery following her recent illness, and today she presented the Queen's Gold Medal for Poetry and held a series of audiences," officials from Buckingham Palace said in a statement.
"However, regrettably, she will no longer attend the Tech City engagement planned for tomorrow, or the Soldiers' and Airmen's Scriptures Association Service at the Guards Chapel on Thursday."
The Queen will continue to perform other duties at Buckingham Palace, including holding a Privy Council meeting Wednesday, the statement said. Other members of the royal family will make appearances on her behalf.
"The Queen hopes to resume her programme of official engagements next week."
The 86-year-old Queen stayed overnight in hospital last week due to a stomach bug.