Turns out biodegradable plastic bags might not live up to their name.

Overseas research which tested four different types of biodegradable plastic bag, found that after spending three years being exposed to the water, earth, sun and air, the majority of them were completely intact and still usable.

The only one that did degrade was the compo stable bag when left in water for three months.

To top it all off, the study also found that reusable cloth bags are not better for the environment.

Organic materials group chair, Chris Purchas, told Mike Hosking just because something is labelled as "biodegradable" doesn't mean it is.

"There is a lot of confusion out there and what we have been focused on doing is trying to provide really good information for consumers."

"At the moment we are working on a guideline for product owners or the suppliers of those bags to make sure that they are able to back up the claims that they are making in their marketing material."

Purchas said there is clearly a demand for more environmentally friendly products.

But he said we need to make sure that these products actually are better for the environment.

"The key thing is that there are standards for various claims that can be made. We aren't about making an assessment about particular products, we are saying look for the European standards, look for the Australian standards and look for products that comply with those."

He said under the Advertising Standards companies need to be able to substantiate any claims they make.

Purchas said they are working with the Commerce Commission to ensure biodegradable plastic bags actually meet the required standard.