Postal workers who drop red rubber bands used for bundling letters in the street are being targeted by anti-litter campaigners.
Keep Britain Tidy is warning that those caught dropping litter face on-the-spot fines of £80, and says postal workers should not be above the law.
It claimed 6% of England's streets were littered with rubber bands, which could be dangerous to animals if swallowed.
The Royal Mail said it regularly told its staff to avoid littering.
The figures follow the charity's Local Environment Quality Survey, which records what litter is found on 19,000 streets across England each year.
Fines for littering can reach as high as £2,500 in cases that go to court.
Keep Britain Tidy is calling on Royal Mail to tackle the issue, and is asking residents to collect up discarded red rubber bands as part of its Big Tidy Up campaign.
The charity's Dickie Felton said: "Elastic bands may not be as visually offensive as dog dirt or half-eaten pizza, but they are most definitely litter.
"Royal Mail staff who drop elastic bands could potentially face prosecution for littering. Is is really too much to ask them to put the rubber bands in their pocket as they do their daily rounds?"
Mr Felton suggested the move might also save Royal Mail money.
A Royal Mail spokesman said: "Royal Mail regularly stresses to its postmen and women the importance of avoiding litter and the vast majority of our rubber bands are recycled, with millions being re-used every week."