Prime minister Mark Rutte has asked the Council of State to advise him on how to deal with information about spending on the royal family, following widespread media speculation about the cost of restoring one of the king’s coaches.

The Council of State is the government’s most senior advisory body and the country’s highest administrative court.

Last month Rutte told MPs that the cost of carrying out restoration work on the king’s golden coach would not be made public because such information would conflict with the constitution. The Dutch constitution states the king has the right to organise the royal household as he sees fit.

However, MPs are continuing to press the prime minister to make more information public. Rutte said in answer to D66 leader Alexander Pechtold that he wants the Council of State to say how far he is able to go.

The coach was given to queen Wilhelmina by the city of Amsterdam in 1898 to celebrate her inauguration.

Similar questions have also been raised about the cost of maintaining the former queen’s yacht. According to the Volkskrant, the yacht has cost the Dutch state €1.5m in maintenance over 11 years.

Princess Beatrix – queen of the Netherlands until she abdicated in 2013 – was given De Groene Draeck yacht by the Dutch people for her 18th birthday in 1957.