Men at Work's Colin Hay has hit back at a ruling that his song Down Under rips off a popular children's tune, calling it a win for corporate greed.

The Federal Court found the flute riff in the song was originally from the tune of Kookaburra Sits In An Old Gum Tree.

In an open letter to fans, Hay maintains the ruling will not change his feelings for the Australian classic, which he penned with Ron Strykert over 30 years ago.

While Hay went on to maintain the flute riff was not part of the original song so therefore should not be considered an infringement of copyright, the statement focuses on his anger at how the case has been publicised.

"The copyright of Kookaburra is owned and controlled by Larrikin Music Publishing, more specifically by a man named Norm Lurie. Larrikin Music Publishing is owned by a multi-national corporation called Music Sales," he said.

"I only mention this as Mr Lurie is always banging on about how he's the underdog, the little guy. Yet, he is part of a multi-national corporation just like EMI Music Publishing. It's all about money, make no mistake."

He says Marion Sinclair, who wrote Kookaburra, never complained about the similarities and there were enough differences between the riffs to consider them separate tunes.

"It is no surprise that in over 20 years, no one noticed the reference to Kookaburra. There are reasons for this. It was inadvertent, naive, unconscious, and by the time Men At Work recorded the song, it had become unrecognisable," he said.

"It is also unrecognisable for many reasons. Kookaburra is written as a round in a major key, and the Men At Work version of Down Under is played with a reggae influenced 'feel' in a minor key. This difference alone creates a completely different listening experience.

"The two bars in question had become part of a four-bar flute part, thereby unconsciously creating a new musical 'sentence' harmonically, and in so doing, completely changed the musical context of the line in question, and became part of the instrumentation of Men At Work's arrangement of Down Under."

Hay also says the ruling will hamper musical creativity across the industry.

"What was born out of creative musical expression, became both a technical and mathematical argument. This ruling will have lasting repercussions, and I suspect not for the better," he said.

His statement ends on a defiant note, reaffirming his commitment to the song.

"This outcome will have no real impact upon the relationship that I have with our song Down Under, for we are connected forever. When I co-wrote Down Under back in 1978, I appropriated nothing from anyone else's song. There was no Men At Work, there was no flute, yet the song existed," he said.

"That's the truth of it, because I was there, Norm Lurie was not, and neither was Justice Jacobson. Down Under lives in my heart, and may perhaps live in yours. I claim it, and will continue to play it, for as long as you want to hear it."