Queen Elizabeth has missed a New Year's Day church service on Sunday due to a heavy cold, Buckingham Palace said, a week after the 90-year-old monarch missed a Christmas Day service for the first time in decades.

Elizabeth, the world's longest-reigning monarch, became unwell before Christmas and has been staying indoors at her Sandringham country estate.

"Her Majesty The Queen will not attend Sunday worship at Sandringham today," the palace said in a statement.

"The Queen does not yet feel ready to attend church as she is still recuperating from a heavy cold."

Elizabeth and her husband Prince Philip, 95, were both suffering from heavy colds in the week leading up to Christmas and delayed their journey from London to Sandringham by a day, travelling there by helicopter on December 22.

Philip was driven to the traditional Christmas service at the parish church of St. Mary Magdalene in Sandringham, but the queen, who is the symbolic head of the Church of England, did not attend.

The Duke of Edinburgh is expected to attend the New Year's Day service.

Elizabeth had previously attended the Christmas service at the church every year since the royal family started celebrating Christmas there in 1988.

After more than six decades on the throne, the queen has cut back on international tours but still regularly performs official duties around Britain.