A draft new law, setting legally binding targets for cutting plastic waste and pollution, will be re-introduced to Parliament on Thursday by Alistair Carmichael.
It comes despite public concern about the scourge of plastic pollution over the past three years, and a number of initiatives.
But Shetland’s MP says far tougher action is needed by the UK government to tackle the problem.
He has pointed to a growth in the problem over recent months, with discarded single-use face masks.
Mr Carmichael said: “We need firm action on plastic pollution now, well beyond what we are already doing on climate change.
“Plastic pollution has not gone away with arrival of the pandemic and in some ways we have reversed progress – we have all seen the new scourge of disposable face masks around town. “