Kim Jong-un warned there is a “nuclear button” on his desk as he threatened the US during his New Year’s speech in Pyongyang.
Donald Trump has pledged to “take care” of Kim Jong-un’s ruthless regime but has not yet succeeded.
Mr Waltz said President Trump must consider “every option” as the US prepares to fight back Kim Jong-un’s nuclear threats.
War veteran and author Michael Waltz told Fox News: “At the end of the day, I think I would like to see us try a blockade before we go to the final military option.
“But we do risk also a slow escalation at sea and we could risk losing the benefit of surprise by a precision strike on the nuclear programme and on the leadership.”
A naval blockade on North Korea would stop the inflow of oil, machinery and raw materials that could benefit the rogue nation’s nuclear regime.
North Korea state media outlet KCNA responded to the claims and said: “Should the US and its followers try to enforce a naval blockade against our country, we will see it as an act of war and respond with merciless self-defensive counter-measures as we have warned repeatedly.”
Mr Waltz said the naval blockade must be part of an overall strategy to bring down North Korea. But he said China is the key to stopping its plans for a fully-fledged nuclear missiles programme.
Mr Waltz said: “I still would like to see us absolutely focussed on China and choking off and encouraging the Chinese to choke everything off North Koreans.
“Remember, they still have a very long land border with North Korea. They have an oil pipeline.
“What we’d risk with a blockade is that we tie down our Pacific Fleet while the Chinese are still supplying the North Koreans because to them it is more of our problem than it is a Chinese problem.”
In an effort to stop the rogue nation, the United Nations Security Council imposed tough sanctions on North Korea after its continued missile testing.
The resolution seeks to ban nearly 90 percent of refined petroleum product exports to North Korea.
Following the UN vote, Donald Trump wrote on Twitter: “The United Nations Security Council just voted 15-0 in favour of additional Sanctions on North Korea. The World wants Peace, not Death!”
The North Korea foreign ministry responded to the UN sanctions and branded them an “act of war” and said: “We define this ‘sanctions resolution’ rigged up by the US and its followers as a grave infringement upon the sovereignty of our Republic, as an act of war violating peace and stability in the Korean peninsula and the region and categorically reject the ‘resolution’.
“North Korea’s nuclear weapons are a self-defensive deterrence not in contradiction of international law.
“We will further consolidate our self-defensive nuclear deterrence aimed at fundamentally eradicating the US nuclear threats, blackmail and hostile moves by establishing the practical balance of force with the US.”