Greenpeace wants new taxes on plastic for Wales
Environmental campaign group Greenpeace has called for Welsh ministers to consider taxing plastic waste.
The Welsh Government has called for ideas that could be developed into new levies.
Greenpeace said powers over new taxes could be used to tax coffee cups or "problem" plastics that cannot be recycled.
The Welsh Government said a shortlist of possible new taxes would be published on 3 October.
The calls from Greenpeace follow the Welsh Government's decision to proceed with a ban on microbeads - small pieces of plastic - being used in cosmetics in Wales, following action taken by the UK government.
The campaigners said 7,500 people have signed a petition calling for the Welsh Government to use tax powers it now has to "deal with the problem of plastic pollution".
Under the Wales Act 2014, the Welsh Government can put forward proposals for the development of new taxes in areas of policy controlled from Wales.
However, they must be agreed by AMs, the UK government, the House of Commons and the House of Lords.
Tisha Brown, oceans campaigner at Greenpeace UK, said: "Wales was ahead of the curve on the plastic bag charge and we'd love to see it taking a lead on tackling ocean plastic pollution."
She added that the petition calls "on the Welsh Government to introduce measures like bottle deposit return schemes to tackle the millions of single-use plastic bottles which are clogging our oceans, action on throwaway coffee cups, and tackling problem plastics like polystyrene which can't be recycled".
Paper coffee cups are fused with polyethylene which means they cannot be easily recycled.
A Cardiff University study said charging for coffee cup use could cut their use by 300 million a year in the UK.
Greenpeace is not the first to call for a deposit return scheme in Wales - which would allow users of plastic bottles to be given a deposit when they return the items for recycling - Scotland has announced it will launch its own project.
In April the Marine Conservation Society said figures showed "a steady rise" in the number of caps, lids and glass bottles found on Welsh beaches in the past five years.
A Welsh Government spokesman said: "We will work with experts and taxpayers to develop a new tax proposal to take to the UK government next year.
"Thanks to a comprehensive package of innovative recycling policies, funding and statutory targets, our recycling rate is now the third best in the world.
"To build on this success we are now examining options to further increase recycling and reduce waste through an extended producer responsibility scheme. This includes a review of the potential for a deposit return scheme in Wales."