"We're not looking for a conflict," Powell said. "We want denuclearization of the Peninsula. So do our neighbors and friends in the region, North Korea's neighbors.
"And I think we'll get it and I think the North Koreans will be better off when they have irreversibly and permanently eliminated this capability," he said in an interview with an Atlanta radio station.
Powell's comments came as the State Department's top East Asia policymaker James Kelly on Wednesday hosted bilateral meetings on North Korea with counterparts from Seoul and Tokyo, ahead of an informal three-way session on Thursday.
The three allies coordinate closely on policy towards the Stalinist state and were likely to discuss the latest developments in China's drive to convene a new round of six-nation crisis talks after a first round made little headway in August.
South Korea was represented in Washington by deputy foreign minister Lee Soo-Hyuk, while Japan sent its director general of Asian and Oceanian Affairs Mitoji Yabunaka, the State Department said.
The United States revealed this month it had made a rare direct call to North Korea in a bid to convene a second round of the six-party talks, which were expected in December but never happened.
North Korea offered recently to freeze its nuclear weapons drive in return for concessions, including an end to US sanctions and a resumption of energy aid.
Washington is holding out for a commitment from Pyongyang to scrap its nuclear program.
The discussions came as top US nuclear scientist Siegfried Hecker detailed his trip two weeks ago to North Korea's notorious Yongbyon nuclear plant, as part of two unofficial US delegations.
He told the Senate Foreign Relations committee that the Stalinist state likely had the capacity to make weapons grade plutonium, but did not prove it had already made or could develop nuclear bombs.