Speaking at a humanitarian meeting on the sidelines of the G20 summit on Friday, Ban called on world powers to put aside their differences over the Syrian conflict, and to take concerted action to get desperately needed aid to the population.
"I must warn that ill-considered military action could cause serious and tragic consequences, and with an increased threat of further sectarian violence," Ban said.
About a third of Syria's pre-war 20.8 million population has fled abroad or have been forced from their homes during the war which is now in its third year, UN refugee agency data showed.
"This is a humanitarian crisis of unprecedented proportions in recent history," Ban said.
But "as some flee the country, others dig in to fight," Ban said, pointing to the need therefore to "avoid further militarization of the conflict and revitalize the search for a political settlement instead."
With a political solution proving elusive as world leaders dig in their heels over their entrenched positions, Ban called for unity in securing humanitarian aid for the population.
A funding shortage was also threatening to leave refugees in neighboring countries with no food, he said, adding that stocks would run out within days in Lebanon and within two weeks in Jordan.
"The world must do everything within its powers to stop the suffering of the Syrian people. Let us use this united recognition of the problem as our starting point for focused and positive action," he added.
"Your support in exercising leverage on all parties to facilitate humanitarian access is critical."
The call for military action against Syria intensified after foreign-backed opposition forces accused the Syrian government of launching a chemical attack on militant strongholds in the suburbs of Damascus on August 21, which killed hundreds of Syrians.
The Syrian government has repeatedly said the deadly attack was a false-flag operation carried out by the militants in a bid to draw in foreign military intervention.
The Obama administration has, however, said it “has the right” to attack Syria even if the Congress does not approve the measure.
NTJ/BA