Publishers Association president Sam Elworthy said everyone was proud of Catton's achievements on the world stage and to see her work given away without her consent by a fellow Kiwi company was "appalling".
"Mega should do more to ensure this kind of thing does not occur," he said.
Mega chief executive Vikram Kumar said two links to Catton's novel were taken down from the site yesterday morning.
Mr Elworthy said the discovery of Catton's work on the Mega site was the "tip of the iceberg".
"Just a few weeks ago we had to ask Mega to take down an entire educational textbook written by a New Zealand author ... which had been made available on their site. This type of illegal sharing is happening at an alarming rate and really hurting New Zealand creatives.
"While Eleanor Catton is doing big things for our international reputation, it's disappointing to see her being ripped off by a website which calls itself a New Zealand company," Mr Elworthy said.
This doesn't surprise me at all. How this guy ever came to be allowed to reside in NZ is beyond me and to see the way he is courted and promoted by media here sickens me.