The Dutch royal family expressed regret on Wednesday for inviting 21 people to Princess Amalia's 18th birthday last week.
Under current COVID-19 rules, people in the Netherlands can receive a maximum of four guests over the age of 13 at home.
"The king informed me that after some thought it was not good to have organised (the party)," Dutch Prime Minister Mark Rutte explained in a letter to Parliament.
The birthday for the future Queen was held outside in a park belonging to the palace last Saturday. Guests were asked to get a COVID-19 test, be vaccinated and respect social distancing.
The letter does not say how many guests attended the event, which was also criticised by several parliamentarians.
"If we make exceptions for the royal family, all our measures fall apart," said MP Eva van Esch from the "Partij voor de Dieren" (Party for the Animals).
Another MP, Caroline van der Plas from the BoerBurgerBeweging party (Citizen Farmer Movement) said many birthdays are postponed, adding that the family was not aware of its role in setting an example.
Amalia celebrated her 18th birthday on December 7, and immediately entered the Dutch Council of State, the government's highest advisory body, where she automatically sits after becoming an adult.
The celebrations surrounding Princess Amalia's birthday follow a series of missteps by the Dutch monarchy during the pandemic, which has had an impact on its popularity.