George Clooney has stepped down from a United Nations role as a "messenger for peace" because he no longer has the time for the position.

UN spokesperson Stephane Dujarric said on Monday that Clooney, who recently got engaged, had decided stop promoting its peacekeeping efforts. "After six years in this role, Mr Clooney feels it is time to retire his official role as messenger of peace," he said. "The competing demands on their time from their professional and advocacy lives sometimes make it difficult for high-profile individuals to carry out a formal United Nations role."

Clooney's engagement to human-rights lawyer Amal Alamuddin was confirmed by her employer, London's Doughty Street Chambers, and by Clooney's mother. Celebrity news sites have reported that Clooney proposed to the Beirut-born barrister sometime in the past two weeks.

Dujarric congratulated Clooney on his engagement and said that UN secretary general Ban Ki-moon hoped the actor would be involved with the organisation in some form in the future. "Retiring from his UN role will afford him the independence to move forward with this and other personal advocacy projects and activities," he said.

Clooney was named as a messenger of peace in 2008 following his work raising awareness of the displacement of millions of people in Darfur, in western Sudan. In 2010, he co-founded the Satellite Sentinel Project to chart violence and human rights abuse in the region, and he has travelled to both Sudan and the Democratic Republic of Congo in his UN role.