In a statement issued in Calcutta, the UFDB chairman, Thinley Penjore, said the King was just bringing back reforms he had already cancelled.

The reforms were originally introduced in 1971 by the king's father, Jigme Dorji Wangchuk, to reduce the absolute power of the monarchy.

They include measures allowing the Bhutanese national assembly to force the monarch to abdicate.

Thimphu - Bhutan's capital

Under the new rules, the king will have to stand down in favour of the crown prince if there is ever a two-thirds majority in the assembly in favour.

King Wangchuck has also given the assembly the right to elect the majority of members in the country's cabinet.

He said the King had put his own supporters in key positions in the Bhutanese national assembly before offering it the opportunity to challenge royal decisions.