Emperor Akihito, on the occasion of his 75th birthday on Tuesday, said both he and Empress Michiko are hoping to support Crown Prince Naruhito and Crown Princess Masako, who will one day assume the positions of emperor and empress.

"Both Her Majesty and I earnestly wish for the health of the Crown Prince and the Crown Princess, and hope to continue to support the two of them, who will be assuming weighty positions in the future," the Emperor, who has been suffering from stress-induced stomach problems, said in a statement.

His comments come amid mounting speculation that his stress might have stemmed from a tiff with the Crown Prince over his often reclusive wife, the Crown Princess.

It is believed the row between the Emperor and his son started after the Crown Prince said in May 2004, "It is true that there were developments that denied Princess Masako's career as well as her personality driven by her career."