The former Tory leader called on the US to be “prepared for anything” but played down the prospect of all out war with the rogue state.
He said Kim Jong-un’s regime had to be shown that it would come up against “overwhelming military might” if it ever did choose to wage war with America.
The former Foreign Secretary spoke to BBC Radio 5 Live’s Emma Barnett after North Korea launched another missile into the Sea of Japan, sparking further fears Kim Jong-un could trigger World War 3.
Lord Hague said: “I think that they [USA] should be prepared for anything and that really means the United States prepared for anything, I don’t think the UK would have a major role in any military action, horrendous as it would be in any case for any military action to arise.
“In this case, they should be prepared for that but there’s unlikely to be a military solution to this.
“A war in the Korean peninsula could result in millions of deaths, it could be the worst event in the world since the Second World War so we have to be strong and show that North Korea would come up against overwhelming military might if it did venture into a war but a military solution is unlikely.”
The life peer also said Donald Trump was wrong to promise “fire and fury” if North Korea targeted any US territory.
He suggested the US had to “speak softly and carry a big stick”.
Lord Hague also echoed Theresa May’s calls for China to do more in the fight to stop North Korea developing nuclear weapons and carrying out provocative missiles blasts.
She said: “The actions of North Korea, of DPRK, are illegal. They are significant actions of provocation.
“I think it’s outrageous. That’s why we will be working with our international partners, as we have done previously but we will be doubling our efforts with our international partners to put pressure on North Korea to stop these illegal activities.”