Ban "urges the parties to refrain from taking any further measures that might increase tensions," said his spokeswoman Eri Kaneko.
North Korean leader Kim Jong-Un put his frontline troops on a war footing on Friday, a day after an exchange of artillery fire across the demilitarized border that put the South Korean army on maximum alert.
Ban, who served as South Korea's foreign minister from 2004 to 2006, said he was "deeply concerned" by the developments and called for dialogue to reduce tensions.
North Korea wrote to the UN Security Council this week to again request an urgent meeting on the military exercises, but diplomats said nothing was planned.
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The exercise, which will run until August 28, is largely a computer simulation of a North Korean attack, but still involves 50,000 Korean and 30,000 US soldiers.
North Korea's Deputy UN Ambassador An Myong Hun scheduled a news conference at UN headquarters for 2000 GMT.