Plastic makes up the majority of Aussie marine litter

Plastic debris makes up the majority of litter found in Australia's urban waterways. (Bianca De Marchi/AAP PHOTOS)

Plastic made up more than three-quarters of the litter collected from Australia's urban waterways and catchments in the past three years, new research shows.

Food wrappers, polystyrene, bottle caps and unidentifiable shards of hard and soft plastic were the most common items found, according to Conservation Volunteers Australia.