World leaders paid tribute to former UN Secretary-General Boutros Ghali, praising his leadership of the international body during what they say was one of the most difficult periods.

Washington said it is "saddened" by the passing of the senior Egyptian diplomat who died Tuesday in Cairo aged 93.

"Egypt – and indeed, the world – lost a distinguished statesman," Samantha Power, US permanent representative to the UN said in a statement early on Wednesday.

Boutros Ghali was the United Nations' first secretary-general from Africa and the only Arab to ever hold the post.

Boutros Ghali served as the United Nation's sixth secretary-general, holding the post from 1992 until 1996.

Power said Ghali oversaw the world body "during a tumultuous time" that included the aftermath of the collapse of the Soviet Union. She hailed his role in forging a groundbreaking peace agreement between Egypt and Israel during a landmark trip to Jerusalem with president Anwar Al-Sadat as foreign minister.

The 15-member UN Security Council held a moment of silence after his death was announced at the beginning of a meeting in New York on Tuesday.

French President Francois Hollande paid tribute to Ghali, saying this "great Egyptian and great servant of the United Nations" never stopped fighting to preserve peace and to avert conflicts worldwide.

Hollande said Ghali's message of peace must "inspire the international community's action at a time when the Middle East is experiencing new tragedies."

UN Secretary-General Ban Ki-moon said Ghali led the organisation through "one of the most tumultuous and challenging periods in its history."

"He showed courage in posing difficult questions to the member states and rightly insisted on the independence of his office and of the secretariat as a whole," Ban said.

British Foreign Secretary Philip Hammond said Boutros Ghali’s "contribution to international affairs will long be remembered."