The composers of the 1980s hit Down Under must pay a share of earnings from the song after it was discovered that there was a breach of copyright law.

In February, Federal Court Justice Peter Jacobson said that the flute riff from Men at Work's track was undeniably similar with the children's song Kookaburra Sits in the Old Gum tree.

The original melody was done 75 years ago by Marion Sinclair, a Toorak teacher, for a Girl Guides competition and Larrikin Music now has its copyright ownership.

In the Federal Court in Sydney on Tuesday, Justice Jacobson ordered music group EMI and Down Under songwriters Colin Hay and Ron Strykert to give five per cent of royalties from the song dating back to 2002 and from future earnings to Larrikin.

The figure was well below the up to 60 per cent demanded by Larrikin.

"I've come to the view that the appropriate figure ... is five per cent," Justice Jacobson said.

"In my opinion the figures put forward by Larrikin are over-reaching, excessive and in my view unrealistic."

The song Down Under was released back in 1982 and went to number one on the Australian, British and American charts.

Justice Jacobson said that when calculating the percentage payable he had to consider the weight of "the significance of the bars of Kookaburra to the overall musical qualities of Down Under".

"Whether the hypothetical bargain is assessed at 1982 or 2002, the percentage interest payable is at the lowest end of the spectrum," he said.