“These people are bringing [trolleys] out here, it’s not nice, they are defacing the place,” he said.
Charging supermarkets for dumped trolleys, “is a good idea”, he added.
Newport council said it would look to collaborate with Natural Resources Wales (NRW) to recover trolleys from rivers, as it “cannot assume responsibility for recovery operations” due to a lack of resources.
The environmental watchdog said responsibility for removing waste from rivers fell to the landowner.
A NRW spokesperson said: “We are working hard to try to keep waste out of rivers to the best of our ability, but there is no simple solution to this societal challenge.
“We need a collaborative and catchment-wide solution, with a mixture of better waste management, enforcement and education – not something any one organisation can do alone.”