"The queen will regrettably no longer attend the Commonwealth observance at Westminster Abbey today as she continues to recover following her recent illness," a Buckingham Palace spokesman said.

The queen, who was discharged from hospital a week ago, is otherwise in good health and was still expected to attend a reception in the evening, the spokesman said. She will also attend some of her official engagements planned later this week.

Last Monday, the 86-year-old British monarch left hospital after three days of treatment for a stomach bug, having been forced to cancel a planned visit to Italy.

It was the first time in 10 years that Elizabeth, who rarely cancels official engagements, had been hospitalized. Despite cutting back on a once hectic timetable of foreign visits, she is still renowned for her stamina in dealing with a busy schedule at home.

However, officials were quoted in British media as saying her current health problems were not serious and there was nothing to worry about.