This photo taken on February 12, 2017 and released on February 13 by North Korea's official Korean Central News Agency (KCNA) shows North Korean leader Kim Jong-Un (C) surrounded by soldiers of the Korean People's Army as he inspects the test-launch of a surface-to-surface medium long-range ballistic missile Pukguksong-2 at an undisclosed location.

The United States has failed to put in place enough senior diplomats to tackle the North Korean nuclear threat and trade issues in East Asia, international policy experts told an audience this week.

"You'd think we're going into a crisis with North Korea, and there's no ambassador in Seoul, in Tokyo, in Beijing or an assistant secretary for East Asia. You wonder, beyond the tweets and what the White House says, how actually the work of the government is going to get done," said Vali Nasr, dean of the Johns Hopkins School of Advanced International Studies and a former senior advisor on Afghanistan and Pakistan under Ambassador Richard Holbrooke.

The U.S. State Department website says that those major ambassadorships are "vacant" — as are the top U.S. diplomatic posts to India and Australia — even as smaller countries such as the Philippines have ambassadors in place.

In a statement to CNBC, the State Department pointed out that it has officials "serving in acting capacities" in those countries. The department deferred to the White House on senior nomination questions.

The White House did not respond to a CNBC request for comment.

"You worry that even if things are calm, you're just one step away from a very big crisis," Nasr said. He was speaking Wednesday evening at the Asia Society in New York.