Former Australian Test speedster Lee left the outspoken Brit battered and bruised after peppering him with a six-ball, short ball assault in the MCG nets during tea on day two of the Boxing Day Test.
Hadlee, New Zealand's greatest cricketer, said the exhibition should not have been shown on live television as Lee could have killed the hapless Morgan.
"I only hope that Brett takes a few minutes to reflect on his stupidity - this was a brain explosion of the highest order - it was a deliberate attempt to hit, injure, hurt and maim his opponent that I viewed as a form of grievous bodily harm or a human assault that could have proved fatal," Hadlee wrote for Fairfax NZ News.
Hadlee added that Lee's actions had damaged cricket.
"There will be many mums and dads around the world who saw that exhibition and may decide to stop their kids from playing the game, such was the brutality and the risk to someone's life," he added.
The stunt evolved after Morgan questioned the courage of England's batsmen against Australian quick Mitchell Johnson during the Ashes series and Lee challenged Morgan to pad up.
"The ICC has an edict of fair play and upholding the spirit of the game, but that exhibition compromised those values," Hadlee said.
"I only hope that officialdom will review the incident and if necessary take some action against Lee's behaviour - perhaps a censure, fine or even a suspension for his act of stupidity and misjudgment.
"Lee will have to accept there are no words than can be used to justify his decision-making and how he executed that six-ball over - it was beyond comprehension.
"Given the same situation, if I wanted to embarrass Morgan for tweet jibes I would have taken more pleasure out of trying to hit the stumps six times than deliberately trying to hit him."