“People are paying too high a price. We need a whole new approach,” Guterres said on Tuesday in his first address to the Security Council since taking office in January.
Guterres, who succeeded Ban Ki-moon on January 1, has vowed to shake up the world body and boost efforts to tackle international crises, including the conflict in Syria and the bloodshed in South Sudan.
He expressed regret that too much time and resources have been spent on responding to crises rather than preventing them.
The former Portuguese prime minister called for “a surge in diplomacy for peace” and urged the world body to make greater use of the measures in the UN Charter to find peaceful solutions to the ongoing disputes.
He said it has proved very difficult to persuade national and international decision-makers to prioritize prevention, perhaps because “the television cameras are not there when a crisis is avoided."
The new UN chief is faced with a deeply divided Security Council that has failed to take decisive action to put an end to the nearly six-year foreign-backed militancy in Syria.
“Too many prevention opportunities have been lost because member states mistrusted each other's motives, and because of concerns over national sovereignty," Guterres said.
“Today, we need to demonstrate leadership, and strengthen the credibility and authority of the United Nations, by putting peace first,” he added.
Speaking in an interview with Portugal's SIC television channel on December 28 before taking office, Guterres said the crisis in Syria "has become a cancer on a global scale."
He also noted that the conflict has caused "not only the suffering of the Syrian people" but also ignites "violent reactions which in some cases lead to terrorist acts."
Since March 2011, Syria has been gripped by deadly militancy it blames on some Western states and their regional allies.
The so-called Syrian Observatory for Human Rights and United Nations Special Envoy for Syria Staffan de Mistura have put the death toll from the conflict at more than 300,000 and 400,000, respectively. This is while the UN has stopped its official casualty count in Syria, citing its inability to verify the figures it receives from various sources.