Prime minister Mark Rutte has warned that making the king pay income tax will be an “extremely complicated process” but nevertheless one which he is “not entirely opposed to”.

Speaking during a debate on his ministry’s 2024 spending plans, Rutte said he did not oppose making the king pay income tax in principle but said “we should not be making a law for the four people in the royal household who are paid by the state”.

“It would be very complex,” the caretaker prime minister said.

There is now at least a two-thirds majority in favour of making the royals pay income tax on the money they get from the state, which will hit €8.6 million this year.

During the debate, other MPs called for the king’s €55,000 pay rise to be scrapped and said that cars with an AA number plate – those used by the royal household – should also be liable for road tax.

Later, however, it emerged that the pro-countryside BBB, with seven MPs in the lower house, has its doubts about taxing the king. “I’m still wrestling with the idea,” said parliamentarian Mona Keijzer. “I see both benefits and drawbacks.”

At least two-thirds of MPs and senators are needed to back a change to the constitution and force the king to pay income tax.

The royal family get a combined pay rise of €600,000 this year, in line with civil service salaries and as compensation for inflation.

The king’s package will rise by €55,000 to almost €1.1 million, while Maxima’s salary goes up to €431,000. Crown princess Amalia is also entitled to a pay package but has opted not to take any government cash until she has graduated from university.

The taxpayer also picks up the bill for security, rebuilding palaces and foreign tours and in total, the cost of the royal family will rise some 11% next year to €55 million.