Surfers Against Sewage says it has seen an "explosion" of discarded masks and plastics on beaches and in rivers.
The group claims businesses are using the pandemic to revert to using huge amounts of single-use plastic.
From September, it plans to name and shame on social media individual companies whose waste its members most regularly find.
Image copyrightPETER COXImage captionA new campaign against plastic pollution will launch in September
Jack Middleton from Cornwall-based Surfers Against Sewage said: "Since lockdown has started to be lifted we've witnessed a new wave of plastic pollution littering our beaches in the form of disposable masks and gloves.
"While the PPE has helped to save lives over the past few months, we now need to consider how we dispose of it properly to prevent it from flowing into our rivers and oceans and destroying our beaches.
"We're used to seeing plastic bottles and bags when we're surfing but this new type of plastic pollution is something that no-one could have foreseen."
Mr Middleton encouraged people to use reusable face masks and said measures introduced to help businesses during lockdown were undermining the battle against plastic pollution.
Image copyrightSASImage captionSurfers Against Sewage say they are seeing PPE turning up on beaches
"We have seen the government roll back on the progress we have made in tackling the plastic pollution crisis," he said.
"The 5p plastic bag charge has been waived for food deliveries and the ban on straws, stirrers and cotton-bud sticks that was just weeks away from being introduced has been postponed."
wow that's good news. that will help all of us. 🧡