Prince Philip has cancelled royal engagements over the coming days as he continues to recover from a bladder infection, Buckingham Palace says.
The Duke of Edinburgh, who turned 91 on Sunday, was taken to hospital on Monday last week, forcing him to miss the end of the Queen's diamond jubilee celebrations marking her 60 years on the throne.
He was released from hospital on Saturday and was expected to resume his program of engagements, but will instead spend more time recuperating.
The Queen and her husband were due to host a party Monday at Sandringham, her private estate in Norfolk.
Prince Philip was also due to accompany the Queen on regional diamond jubilee visits on Wednesday and Thursday.
"The Duke of Edinburgh will be continuing with his convalescence at home and therefore will not attend tomorrow's garden party at Sandringham or accompany the Queen on her east Midlands tour later this week," Buckingham Palace said.
The palace said the couple's second son, Prince Andrew, would now accompany the Queen at Sandringham.
To mark Prince Philip's birthday, two gun salutes were fired in London at midday on Monday.
The King's Troop Royal Horse Artillery's 41-gun salute in Hyde Park was accompanied by a 62-gun tribute by the Honourable Artillery Company at the Tower of London.
Outspoken Philip, the longest-serving royal consort in British history, has been the Queen's stalwart companion throughout her reign.
He is famed for his off-colour jokes, but behind the scenes is said to be a key source of support for the Queen.