There are still gaps in what scientists know about the damage being done to the environment by microplastics, as well as the harm they cause to humans and wildlife.
A new report by the Royal Society has provided a stocktake of the country's reliance on plastic and the challenges to reducing it.
It said there was still a lot that wasn't known about microplastics, which have been notoriously difficult to research because of their tiny size.
More work needed to be done to determine what level of microplastics people encountered in their daily life, through their diet or airborne sources.
Canterbury University environmental chemist Sally Gaw, who contributed to the report, said there were also questions about how this affected people's health.
"Ocean waves, sunlight or abrasion from sand or rocks can break the plastic into smaller and smaller fragments that can then be ingested or breathed in by wildlife on land or in the sea. Humans are also consuming microplastics," she said.
"Researchers are still determining the full impact of this plastic entering the food chain but evidence is mounting that there is good reason for concern, especially as some plastics can contain toxic chemicals."
She told Morning Report estimates were "we could end up with more plastic in the sea than we have fish".
"We're going to have to have a radical break up with plastic or redesign our plastics so that they are more easily degraded to achieve the reductions that are going to be necessary."
Ms Gaw said New Zealand had a higher plastic use and lower recycling rate than some countries.
"We were sending a lot of our plastic offshore for recycling but many countries like China were accepting those used plastics are no longer accepting them, so we have a bit of a stockpile," she said.
"I don't think we can recycle our way out of this problem. It is going to come down to using less plastic."
The report also said there were data gaps in how much and what goes into New Zealand's landfills and recycling bins.
That means no-one knows how much plastic is collected nationally through recycling collections or if it ends up elsewhere.