The Royal Forest and Bird Protection Society of New Zealand wants an immediate extension to a ban on set nets around Otago Peninsula.
A review published in the Journal for Biological Conservation says set nets kill more than 400,000 seabirds around the world every year.
Forest and Bird said yellow-eyed penguins are a prime example of a species whose chances of survival would improve with better controls on set nets.
Spokesperson Karen Baird said 56 birds have been found dead this breeding season - casualties of an unknown toxin.
She said the current 4km ban around the peninsula should be extended to around 20km offshore.
About 150 pairs of the birds still live on Otago Peninsula.