Oceanic plastic pollution is spreading microbes to coral reefs that greatly increase the chance of coral disease.

Where plastic flotsam comes into contact with coral, the likelihood of the presence of a group of coral diseases known as white syndromes rises from 4 per cent to 89 per cent, according to a new paper published in the journal Science.

The international study featuring Australian researchers surveyed 124,000 individual corals in more than 150 reefs between 2011 and 2014.

A third of the reefs were polluted with plastic, with Indonesian reefs emerging as the worst affected.

Australian reefs were found to be relatively unsoiled, showing the lowest plastic concentrations.

But while local reefs appear to have avoided the worst for now, plastic waste is only set to increase. The experts estimate there will be 15.7 billion pieces of plastic littering Asia-Pacific reefs by 2025.