The use of stop and search has increased massively since the SNP came to power, according to the Liberal Democrats.
Justice spokeswoman Alison McInnes said "the power to search an individual without legal cause has been appropriated by the police, without due parliamentary scrutiny and approval".
She questioned how under 10s could possibly have the capacity to consent to a search, saying the practice of stop and search "could amount to discrimination that contravenes the Human Rights Act".
The party has tabled an amendment to the Criminal Justice Bill to end the practice of "voluntary" stop and search, which permits police to request a search without a firm suspicion of criminality.
Kenny MacAskill said he "does not recognise much of this story at all", insisting stop and search is a vital tool to take drugs, weapons and alcohol off the streets.
Ms McInnes said: "The power to search an individual without legal cause has been appropriated by the police, without due parliamentary scrutiny and approval. This is intolerable in a mature democracy.
"In the absence of codification, police are conducting so-called consensual searches with no suspicion of any wrongdoing. There is no requirement to tell people they have a right to refuse. Without this, any consent acquired is ill-informed.
"It is to all intents and purposes a command, based upon exploiting the power gap between officer and subject.
"No authority has yet been able to explain to me how the 500 children under 10 who were stopped and searched in 2010 alone, almost certainly without their parents present, are qualified to give consent. Or the dozens of children aged seven or younger."
Mr MacAskill said: "It is disappointing that the Liberal Democrats have chosen to be so negative.
"Alison McInnes set out a number of concerns about stop and search that brings little if anything in the way of actual evidence of problems to this Parliament.
"She talks about unfounded searches, children being stopped without reason and people's human rights being abused.
"I don't recognise much of this story at all."
Mr MacAskill claimed to "set out the position as it actually is on our streets and in our communities".
He said: "Stop and search is taking drugs, alcohol and weapons off our streets.
"More than 90% of the searches are targeted at these areas and around 20% of these searches are successful."
Labour and Tories both criticised the way stop and searches are currently operated.
Labour MSP Graeme Pearson, a former director general of the Scottish Crime and Drug Enforcement Agency, said it seemed "illogical that stop and searches are currently maintained at a level four times higher than that in England and Wales".
While he accepted stop and search was "an effective tactic", he questioned the "policy endorsement of these tactics and strategy".
Mr Pearson said: "Where was the Scottish Police Authority in deciding that they agreed with the tactic, and where was the debate about the level in relation to such a huge rise in the number of stop-searches?"
He went on: "We live in a democratic country, we expect democratic accountability for police activity which is conducted in our name. But it has become the lament of the Cabinet secretary when questioned on any of these matters that they are 'operational matters' and he leaves that to the chief constable."
Tory Margaret Mitchell said police in Scotland "seek to deter offenders through high volume search activity", but argued there is "no evidence this approach reduces crime".
She added: "Instead it is likely to damage people's trust and confidence in the police and undermine public support for policing, especially amongst young people."
The Conservative called for stop and search to be reformed, but said this must be done in such a way that "public safety is not jeopardised".
She also said more details were needed on the use of stop and search by the police.
"Neither Police Scotland, the Scottish Government nor the Scottish Police Authority routinely publish stop and search statistics," she said.
"As such it is difficult to assess how stop and searches are being carried out, either comparatively across Scotland or at a national level. So more rigorous recording of stop and search statistics is essential to ensuring transparency and accountability is achieved."