"It sounds like it doesn't have any legal legs," he said about the lawsuit, adding that he was not a legal expert.
The Marshall Islands were the site of 67 nuclear tests by the United States over a 12-year period, with lasting health and environmental impacts.
"Our people have suffered the catastrophic and irreparable damage of these weapons, and we vow to fight so that no one else on earth will ever again experience these atrocities," the country's foreign minister, Tony de Brum, said in a statement announcing the lawsuits.
The country is seeking action, not compensation. It wants the courts to require that the nine nuclear-armed states meet their obligations.
"There hasn't been a case where individual governments are saying to the nuclear states, 'You are not complying with your disarmament obligations," John Burroughs, executive director of the New York-based Lawyers Committee on Nuclear Policy, part of the international pro bono legal team, told the AP. "This is a contentious case that could result in a binding judgment."
Several Nobel Peace Prize winners are said to support the legal action, including South African Archbishop Desmond Tutu and Iranian-born rights lawyer Shirin Ebadi.
"We must ask why these leaders continue to break their promises and put their citizens and the world at risk of horrific devastation," Tutu said in the statement announcing the legal action.
The Marshall Islands is asking the countries to accept the International Court of Justice's jurisdiction in this case and explain their positions on the issue.
The court has seen cases on nuclear weapons before. In the 1970s, Australia and New Zealand took France to the court in an effort to stop its atmospheric nuclear tests in the Pacific.
The idea to challenge the nine nuclear-armed powers came out of a lunch meeting in late 2012 after the Nuclear Age Peace Foundation gave the Marshall Islands foreign minister a leadership award, Krieger said.