The trial of the eldest son of Norway's crown princess on charges including rape has begun, after a set of new allegations were made against him.

Marius Borg Hoiby, 29, denied each of the most serious charges, including four counts of rape, when the trial began on Tuesday at Oslo district court.

The charges - 38 in all - also include abuse in a close relationship against one former partner, acts of violence against another and transporting 3.5kg (7.7lb) of marijuana.

Others include making death threats and traffic violations.

Hoiby pleaded guilty to several driving offences, to an aggravated drugs offence and to breaking a restraining order, and "partly" to threats and aggravated assault.

Hoiby is the eldest son of Crown Princess Mette-Marit from a previous relationship and the stepson of the heir to the throne, Crown Prince Haakon. Hoiby has no royal title or official duties.

Following the latest accusations, which are not part of the 38 currently being heard, police said that they would seek permission from a judge to keep Hoiby in their custody for the next four weeks.

Hoiby was free but awaiting trial on the four counts of rape, as well as domestic violence, assault and drug possession, among other crimes.

He could face charges from the latest allegations on top of the 38 counts he already faces.

The existing charges include rape, abuse in a close relationship against one former partner, acts of violence against another and transporting 3.5kg (7.7lbs) of cannabis, as well as making death threats and traffic violations.

Those charges are now being heard at a trial in Oslo, which began on Tuesday. The trial is scheduled to last until March 19.

His lawyer has declined to comment on the new accusations.

Hoiby has been under scrutiny since 2024, when police named him as a suspect of physical assault against a woman with whom he had been in a relationship.

In a statement to the media at the time, Hoiby admitted to causing bodily harm to the woman while he was under the influence of cocaine and alcohol, and to damaging her apartment, saying he regretted his acts.

Hoiby is the son of Crown Princess Mette-Marit from a previous relationship, and the stepson of the heir to the Norwegian throne, Crown Prince Haakon.

He is outside the line of royal succession, and has no title.

Last week, the crown prince said the royal house does not intend to comment during the proceedings.

The trial is opening just as Hoiby's mother faces renewed scrutiny over her contacts with Jeffrey Epstein following the latest release of documents in the US.