Humanitarian agencies are facing dire funding shortages to address a multitude of global crises, the United Nations refugee agency warned Wednesday, saying it alone needed $400 million by the end of the year.

Addressing the opening of the Global Refugee Forum in Geneva, UN refugee chief Filippo Grandi called on donors to strengthen their support.

"Many humanitarian organisations are facing severe funding challenges," he said, pointing out that "UNHCR alone is lacking $400 million to end the year with the minimum of needed resources".

That, he said, was "a shortfall we have not experienced in years, and we are all looking with much concern at 2024."

From Russia's war in Ukraine, the civil war in Sudan and a humanitarian crisis in Afghanistan, conflicts and crises had fuelled record displacement even before the Gaza war erupted.

The number of people displaced worldwide passed 114 million by the end of September, an all-time high.

Grandi said that amounts to "114 million shattered dreams, disrupted lives, interrupted hopes. It is a figure that reflects a crisis - many crises - of humanity".

Among them, nearly 36.5 million have fled across borders and are living as refugees, according to UNHCR -- a number that has doubled in the past seven years and looks set to rise.

"A major human catastrophe is unfolding in the Gaza Strip," Grandi warned, lamenting that "so far the Security Council has failed to stop the violence."

While the war that erupted after Hamas's unprecedented attack inside Israel on October 7 falls outside of UNHCR's mandate, Grandi said the agency expects it could spur "more civilian deaths and suffering, and also further displacement that threatens the region".

While keeping a strong focus on Gaza, he appealed to the international community: "Please do not lose sight of other pressing humanitarian and refugee crises".

He pointed to the millions displaced by conflicts in Ukraine and Sudan, the plight of Rohingya refugees from Myanmar, and the millions who have fled due to conflict and insecurity in Syria, Afghanistan, the Democratic Republic of Congo and across the Sahel.

More than 3,000 people, including heads of state and government and more than 300 refugees, were taking part in the second edition of the forum, which will run through Friday.

Grandi appealed to participants to make the forum "a moment of unity, in which all of us join forces to ensure that those who flee because their life, freedom and security are threatened can find protection, and that everything is done to resolve their exile as soon as possible."