TOKYO (AFP) - Japan's Crown Princess Masako, who has been undergoing treatment for a stress-induced illness for a decade, will travel abroad for the first time in about seven years, government officials said on Friday.

Accompanying her husband, Crown Prince Naruhito, the 49-year-old former diplomat will leave Tokyo on Sunday on an official visit to the Netherlands to attend the coronation of Willem-Alexander on April 30.

It will be her first overseas trip since Mr Naruhito's family spent about two weeks at a retreat in the Netherlands in August 2006 at the invitation of Queen Beatrix.

It will also be her first official visit abroad in 11 years since the couple went to New Zealand and Australia in late 2002.

During the couple's six-day trip, Ms Masako is scheduled to attend the Dutch king's coronation but may skip other events "depending upon her condition", the Imperial Household Agency said.

US-educated Masako has reportedly struggled with the cloistered nature of royal life in one of the world's oldest and most tradition-bound monarchies.

She was diagnosed with an adjustment disorder, according to an official statement in 2004.

Ms Masako married Mr Naruhito, now 53, in 1993 and gave birth to their first and only child, a girl, in late 2001 under intense pressure to bear a son in keeping with Japan's male-only royal succession law.

The pressure seemingly eased when a boy was born to the family of the crown prince's younger brother in 2006, the first prince born to Japan's royal family in 40 years.