The Greens are vowing to put a levy on single-use plastic bags if they're part of the next Government.
Waste spokeswoman Denise Roche says 1.6 billion are used in New Zealand every year, and many of them end up in the ocean.
"Instead of taking real action to remedy this, the Ministry for the Environment is relying on 'be a tidy Kiwi' campaigns and individuals doing the right thing," she said on Monday.
"National seems happy for the status quo, which means more plastic bags polluting our waterways and landfills, and more birds and fish dying needlessly because of them."
Ms Roche says the British government put a 5p (9c) levy on plastic bags which led to an 85 percent reduction in their use and raised £29 million ($52m).
She says a petition asking for a levy went to Parliament's environment select committee, and government officials advised against it.