New Covent Garden Market is aiming to stop people taking waste fruit and veg from skips for their own consumption.
The market authority said so-called totting was becoming a major problem, and those taking the waste didn't realise it had been condemned by Defra as unfit for human consumption.
Most of the scavengers ate the produce themselves, but some were selling it on to restaurants.
The market plans to distribute warning flyers around its site near Vauxhall in south London.
It is also looking at working with Fareshare, which redistributes surplus food to the needy.