An anti-drugs group has aired concern over figures showing that at least 70 children under 16 were arrested for drug dealing in Scotland last year.
Fears have been voiced over drug dealing by schoolchildren
Scotland Against Drugs said it was very worrying that youngsters were coming into contact with criminals.
Strathclyde Police, Scotland's largest force, confirmed that 29 under-15s had been arrested for dealing.
But the Scottish Executive insisted fewer children were being exposed to and taking drugs.
Northern Constabulary said that it had charged 15 under-16s for drug dealing in 2005, while Central Scotland Police confirmed that seven under-16s were recorded for involvement in drug dealing.
It is understood that 14 under-16s were arrested for drug dealing in Lothian and Borders, one a 15-year-old heroin dealer.
Grampian Police said that eight under-16s were detained last year. The force arrested two 13-year-olds for cannabis dealing.
The figures came just days after an 11-year-old in Glasgow was treated for the effects of heroin.
Professor Neil McKeganey, of the Centre for Drug Misuse Research at Glasgow University, said: "It shows that children of a much earlier age than we thought are using illegal drugs.
"The other side of that coin is some of them will sell illegal drugs - that will be their source of income. They will pose the risk of supplying drugs to other children."
He added: "Research published last month showed that some drug dealers in London actually recruited children because they thought those children ran much less risk of being apprehended.
"It would be surprising if there wasn't a similar use of some children in Scotland, at least to do some ferrying of drugs between people."
Deputy Justice Minister Hugh Henry said: "The figures that we have show that fewer children are actually taking drugs and fewer children are actually exposed to drugs.
"But we know that in some communities there is a hardcore minority, but a fairly substantial one in those communities, where there is a problem."
He said that in the next week ministers would be meeting with chief constables, the Scottish Drug Enforcement Agency and with Crimestoppers to look at expanding initiatives targeting dealers.
Mr Henry also challenged parents to do more to stop their children selling drugs.
However, leader of the Scottish Conservatives Annabel Goldie said: "It's just another chilling indicator of how serious the whole problem of drugs misuse in Scotland is.
"We're no longer having to deal with just the big drug barons and the big dealers, we have children trying to sell drugs to their own peer group.
"It's appalling, it's shocking but it's just another indication of how the executive has completely failed to grapple with this problem."