Frans Timmermans told an audience in Ottawa that the cause of nuclear non-proliferation has been set back by the Ukraine crisis, triggered when Russia opted to "simply steal" part of the country.
Timmermans delivered that message in a hard-hitting breakfast speech and question-and-answer session to a small audience of diplomats, government officials and foreign policy experts.
Ukraine eliminated all of its nuclear weapons in a 1994 agreement in exchange for Russia, Britain and the United States respecting the territorial integrity of the country.
Russia, meanwhile, has annexed Ukraine's Crimean Peninsula while pro-Russian gunmen are taking control of cities in the country's east.
"Just imagine what a message this is to Iran: hey, if you give up nuclear weapons, you're at the mercy of those who still have them," Timmermans said.
"It's a horrible message. Just imagine. You have seen the actions of North Korea since."
U.S. researchers have found signs of increased activity at a North Korean nuclear test site, while South Korea warned last week that its totalitarian communist neighbour is readying itself for its fourth nuclear test blast since 2006.
The West, meanwhile, is trying to thwart Iran's nuclear ambitions. There is currently hope that talks between Tehran and the five permanent members of the United Nations Security Council plus Germany might lead to a historic agreement by an upcoming July deadline.
Timmermans said Russia's aggression against Ukraine could be sending a much different message to Iran.
"I believe the only answer to this very negative message ... is for the most responsible nations, the P5 — especially Russia — to open up to the possibility of talks on nuclear disarmament," he said.
"I think that is of the essence."
Timmermans called on Canada, the Netherlands and other countries to step up nuclear non-proliferation efforts, including reaching out to Moscow.
"Once Iran has a nuclear weapon, well, you know other nations in the region will not want to be at Iran's mercy and will want to look for a nuclear weapon themselves. That will have very, very far reaching consequences," he added.
"I'm not one of those who say, 'Well, let Iran have it, it's more stability.' No, no. Iran with a nuclear weapon is more — more — instability."
Timmermans suggested NATO and its Western allies were asleep at the wheel in the years following the fall of the Soviet Union and the end of the Cold War.
But he called on western diplomats to rise to the occasion and not be lulled back into Cold War thinking.
He said Ukraine can have a future that looks towards the European Union but still has relations with Russia.
The current crisis began when Ukraine's pro-Russian president Viktor Yanukovych reneged on an association agreement with the EU, sparking massive demonstrations that eventually led to his ouster.
"The fact that, because there was a disagreement with the government of Ukraine, Russia decided to simply steal part of that country is a sea change in international relations and will have long-term repercussions for the international system," Timmermans said.
Russian president Vladimir Putin is being blamed by the international community for orchestrating the crisis.
Timmermans was in Ottawa for a meeting with Foreign Affairs Minister John Baird and to commemorate the liberation of his country from Nazi Germany by Canadian soldiers at the end of the Second World War.
"Until Russia clearly demonstrates its respect for Ukraine sovereignty and territorial integrity, we will continue to work with our allies and our partners to further isolate Russia, economically and politically," Baird told a news conference.