Mr Healy made a statement to the House of Commons informing MPs of a £2.26 billion loan to help Ukraine, which will be funded by profits from frozen Russian assets.
South Korea’s spy agency said on Friday it had confirmed that North Korea sent 1,500 special operations forces to Russia earlier this month to support Moscow’s war against Ukraine.
Ukrainian President Volodymyr Zelensky also said his government had intelligence that 10,000 troops from North Korea were preparing to join the invading Russian forces.
The defense minister said it was “highly likely” that the transfer of hundreds of combat units from North Korea to Russia had already begun.
Mr Healy told MPs: “North Korean soldiers supporting Russia’s war of aggression on European soil, that is as shocking as it is disheartening.
“North Korea is already sending significant ammunition and weapons to Russia in direct violation of multiple UN resolutions.
“This developing military cooperation between Russia and the DPRK has serious security implications for Europe and the Indo-Pacific.
“It represents a wider, growing alliance of aggression that NATO and the G7 must confront.
“Despite this dangerous development, Ukraine remains determined to fight on its front line in the east and on the Kursk territory.”
He added: “This conflict is now at a really critical point and that is why the UK continues to step up its support for Ukraine.
“Ukrainians are fighting to reclaim their sovereign territory, but they are also fighting to protect peace, democracy and security for the rest of Europe.”
The £2.26bn loan to Ukraine is the UK’s contribution to a $50bn (£38.39bn) loan package agreed by the G7 group of nations, financed through interest on sanctioned Russian sovereign assets.
The money could be used to fund air defences, artillery or other military equipment and comes on top of the UK’s existing £3 billion a year support for Ukraine.
The G7 agreed in June to the loan, using interest on Russian central bank assets held abroad, which were frozen immediately after Vladimir Putin’s 2022 invasion of Ukraine.
Mr Healy said these were “profits from frozen Russian money supporting Ukraine’s fight against Putin, turning the proceeds of Putin’s corrupt regime against that regime and putting it in the hands of Ukrainians”.
He added: “The money that will be used by Ukraine to buy military equipment from British companies, boosting our British jobs and our British industry.”
Shadow Defense Secretary James Cartledge said any number of North Korean troops supporting Russia would be “a major escalation”.
He told the Commons: “I’ve lost count of the many times Vladimir Putin has accused us and our allies of so-called escalation in our support for Ukraine, but today we are considering the very real threat of North Korean troops being sent to support the illegal invasion of Russia.
“Let’s be in no doubt that any potential agreement between Putin and Kim Jong Un to put North Korean boots on Ukrainian soil at all, let alone the numbers that have been reported, would be a serious escalation fever by Putin himself.”
He added: “Both the transfer of North Korean weapons and now the threat of combat troops belie weakness and desperation, as the Secretary of State said, not strength on Putin’s part and above all raise the question of what he is offering North Korea in return.”
During Foreign Office Questions, shadow foreign secretary Alicia Kearns called on the government to “declare North Korea a combatant in the renewed illegal invasion of Ukraine”.
Foreign Office Secretary Stephen Doughty said the government “strongly condemns what North Korea is reported to be doing” and are “deeply concerned about the potential for further transfers, including of ballistic missile technology, which would clearly threaten peace and stability, not only in Ukraine, but in the whole world.”