The Scottish Green Party has led a debate in the Scottish Parliament calling for a tougher code of practice for large supermarkets.
The Greens want local production to be encouraged
The party said that the "big four" supermarket chains were putting local farmers out of business.
Green MSPs want regulations put in place to help encourage local production and aid smaller retailers.
However, the plan has opposition, with the Scottish Retail Consortium disputing the Greens' assertions.
The Greens said the present code of practice governing supermarkets is not working.
The party said it is wrecking livelihoods and communities across Scotland.
Greens claim that Asda, Tesco, Morrison's and Sainsbury's have a stranglehold on milk prices.
Green MSP Shiona Baird said during the debate that high street butchers, bakers and newsagents had been "decimated" by the grip of the main chains.
Ms Baird, MSP for North East Scotland, told the parliament that supermarkets
were dominating farmers and independent retailers, reducing consumer choice.
"Once in the supermarket, what is the choice? The choice between 20 different
kinds of over-processed breakfast cereals or six different thicknesses of loo
paper," she said.
Ms Baird also accused supermarkets of specialising in healthy option ranges
which were over-processed, over-priced, high in fat and contained too much
She said "the real facts" of supermarket trading methods had to be exposed.
"When supermarket prices are cut, they are achieved by squeezing producers,
suppliers and competitors," she said.
The Greens also claim to have worked out that, while prices of common food items like tomatoes, eggs, potatoes and chicken have risen by 47% over the last 15 years, farmers have only seen a 12% rise in prices for their products.
However, Environment Minister Ross Finnie, who labelled the comments "appalling",
said a competitive retail sector was important for the economy.
He added: "Of course there are problems in some sectors, but to condemn the whole of the supermarket industry out of hand on the basis of one or two rather skimpy
pieces of unrelated fact is simply not good enough for a debate in this chamber."
The Scottish Retail Consortium (SRC) said the Greens have failed to take into account transport and storage costs and the code of practice they refer to only applies to direct suppliers, not farmers.
It said the supermarkets are providing better value for money now than they did in the 1950s.
SRC director Fiona Moriarty said profit margins across the supermarket groups
had not increased over the past 10 years.
She added: "Households are spending less on food now than ever before.
Richard Lochhead called for a probe into profits
"In the 1950s, households were spending a third of their income on food,
whilst now we spend less than a sixth of our income on groceries."
Scottish National Party spokesman Richard Lochhead called on the Scottish Executive to investigate each sector's share of the profits "between the plough and the plate", particularly the farmers' share of every pound spent in the supermarket, in order to redress the balance.
Tory agriculture spokesman Alex Fergusson attacked the Greens' description of supermarkets as "simplistic", pointing out the greater choice of food and costs at larger stores.
Scottish Socialist MSP Frances Curran conceded that supermarkets provide cheap food for deprived areas.
But she called for more reasonably priced healthy food such as fresh fruit and vegetables provided locally, particularly through public procurement.