Mr Ban said the conditions were not in place for sending peacekeepers
The time is not right to send United Nations peacekeepers to Somalia, UN Secretary General Ban Ki-moon has said.
On Tuesday US Secretary of State Condoleezza Rice called for a UN force to be sent to the conflict-hit nation.
But Mr Ban said the situation in Somalia was too risky and there was no peace to keep.
There was also very limited world support for a multinational stabilisation force, he added, with few countries prepared to take part.
He had contacted 50 nations - but none had agreed to lead such a force and only one or two were willing to send troops, he said.
Somalia has not had an effective national government for 17 years, leading to a collapse of law and order.
Ethiopia-backed government forces have been fighting Islamist insurgents for the last two years, but the Ethiopian troops are due to pull out next month - leaving only the 3,200-strong African Union peacekeeping force behind.
'No peace to keep'
The danger of anarchy in Somalia was "clear and present", Mr Ban said, and action must be taken.
But he said conditions were not in place for sending peacekeepers.
"If there is no peace to keep, peacekeeping operations are not supposed to be there," the UN chief said.
Instead, he said, more efforts were needed on an inter-Somali peace process and to bolster the current African Union force.
His comments came a day after the Security Council unanimously approved a resolution allowing foreign military forces to pursue pirates on land in Somalia.
Pirates there are currently holding more than a dozen hijacked ships, while attacks in seas off Somalia have increased dramatically in recent months.
The resolution gives authority for one year for countries to use "all necessary measures" by land or air to stop anyone using Somali territory for piracy.