The Government's being told it needs to target the source of the plastics to limit how much of it is around.

A $40 million investment has been announced for converting plastic waste into new products.

Greenpeace oceans campaigner Jessica Desmond told Kate Hawkesby converting plastic is step three, and we need to go back to step one, which is limiting plastics.

"We would really advocate starting with the reduction of anything that is non-essential, so coffee stirrers, straws, disposable cutlery, all of that stuff we should just ban it outright."

Regional Economic Development Minister Shane Jones said the funding would be used to invest in projects that convert waste into materials and products useful to businesses and consumers.

He said the volume of waste going to landfills has increased by 20 per cent since 2008 – "it is time we increased our support for ways of reducing this flow of material".

A high proportion of this waste, particularly recyclable plastic, had other uses and could be converted into new products, he said.