A man from Zwolle has been ordered to undergo psychiatric tests at the Pieter Baan Centre in Utrecht after making threats against princess Amalia and a friend.

The man, named as Wouter G, sent messages and images to the princess via Instagram in which he threatened to rape her and to kill a school friend of hers named as Brent.

G was arrested at the end of January and has been remanded in custody at a psychiatric unit since then. The psychiatric investigation was ordered at a pro forma court hearing on Thursday.

Experts have already established that the man is a paranoid schizophrenic but his lawyer also wants to establish if he is in control of his own actions, news agency ANP said. There is currently a two-month waiting list for assessments at the clinic.

G told the court via a video link that he may have written the messages but that he deleted them the next day and was not aware he had actually posted them.