A constitutional crisis seems imminent in Luxembourg, following the threat of the sovereign, Grand Duke Henri, to impede the proposed law which would give a legal stamp to euthanasia.

Prime Minister Jean-Claude Juncker responded by saying the country would change its constitution to reduce the powers of the sovereign, who traditionally stays above the political fray.

"Because we wish to avoid a constitutional crisis, but at the same time respect the opinion of the Grand Duke, we are going to take out the term 'approve' from article 34 of the constitution and replace it with the word 'promulgate,'" said Juncker, a move which would scrap the sovereign's formal power to block laws.

Juncker's announcement came after Grand Duke Henri, the constitutional sovereign, warned that he would not sign off on a law to legalise euthanasia if it is passed by parliament.

It also came after two hours of talks with political party leaders, leaving little doubt that Juncker had the backing for the move.

Such a constitutional change would require a two-thirds majority in parliament.

"I understand the Grand Duke's problems of conscience. But I believe that if the parliament votes in a law, it must be brought into force," Juncker said earlier, despite his own personal opposition to the bill.

Luxembourg's Justice Minister Luc Frieden said the move was designed to avert a constitutional crisis in the micro-state wedged between France, Germany and Belgium.