The US has delayed an intercontinental ballistic missile test to avoid stoking tensions with the Democratic People's Republic of Korea, as fears escalated that weeks of angry rhetoric could erupt into conflict on the Korean peninsula.

The Pentagon's disclosure that it would reschedule the test due in California next week comes as the international community grows increasingly nervous that the situation could spiral out of control.

A US defense official said Defense Secretary Chuck Hagel postponed the Minuteman 3 test at Vandenberg Air Force Base until next month because of concerns it "might be misconstrued by some as suggesting that we were intending to exacerbate the current crisis with North Korea".

"We wanted to avoid that misperception or manipulation," the US official said. "We are committed to testing our ICBMs to ensure a safe, secure, effective nuclear arsenal."

Pyongyang, incensed by UN sanctions following its nuclear and missile tests and by ROK-US military drills, has issued a series of threats of nuclear war in recent weeks.

It has also reportedly loaded two intermediate-range missiles on mobile launchers and hidden them in underground facilities near its east coast, raising speculation it is preparing for a provocative launch.

Japan will order its armed forces to shoot down any DPRK missile headed toward its territory, press reports said on Sunday.

The order may be issued by Japanese Defense Minister Itsunori Onodera on Sunday or "in a day or two", the Jiji news agency reported.

Under the order, Aegis destroyers equipped with sea-based interceptor missiles would be deployed in the Sea of Japan so they could intercept a DPRK missile if it appeared likely to land in Japanese territory, Kyodo said.

The ROK and the US postponed a major military meeting due to take place in Washington, an official said on Sunday as Seoul was on high alert for potential attacks from Pyongyang.

General Martin Dempsey, chairman of the US Joint Chiefs of Staff, and his ROK counterpart General Jung Seung-Jo were to coordinate policy on the peninsula and other issues during the annual Military Committee Meeting on April 16.

But tensions on the Korean Peninsula are so high that Jung cannot take a long trip away from Seoul, so the meeting will be rescheduled, an ROK Joint Chiefs officer said on Sunday.