Home Office plans to make young offenders wear uniforms while they carry out community service orders have been condemned as a "nasty gimmick".
It was not about "breaking rocks" in chain gangs, said Ms Blears
Probation officers said naming and shaming offenders was counterproductive and would lead to more re-offending.
Rights group Liberty said the plans would only degrade those involved.
But Home Office minister Hazel Blears told the Observer the scheme, which the paper likened to US-style chain gains, would show justice was being done.
Ms Blears said: "People feel very strongly that they don't often see justice being done."
She stressed that she did not want to see offenders "breaking rocks" in chain gangs, as in some parts of the United States, but it would be useful for the public to see them doing something useful.
According to the Observer, one successful scheme in her Salford constituency involved youths being forced to make floral hanging baskets.
But the idea, which the Home Office stresses is not policy, was rejected by the National Association for the Care and Resettlement of Offenders (Nacro).
Head of policy Chris Stanley warned that it could cause vigilante action.
"There's no evidence from anywhere that this type of thing has any deterrent effect," he said.
Assistant General Secretary of the National Association of Probation Officers Harry Fletcher said the idea had previously been rejected because there was no evidence that it worked.
"Introducing uniforms, caps, badges or naming and shaming offenders is likely to degrade them, make them resentful and not turn up for community punishment.
"This will meant the breach rate will soar and more will end up in prison, which is exactly what has happened in the US.
"Half of all reception into prison or custody in the States are for breaching community punishments."
He called for the idea to be "quietly dropped".
The director of rights group Liberty, Shami Chakrabarti, said it seemed that "the cheap and nasty gimmicks" that were a feature of the general election campaign were continuing.
"How do you engender a culture of respect by degrading people?"
Tory former minister Tim Yeo also condemned the idea as a "yet another gimmick" and accused the government of being more interested in "sound bites than in substance".
But Tory Shadow Home Secretary David Davis said: "An idea like this may well make a minor contribution to public confidence, but it will not make up for eight years of neglect of law and order."
Commons leader Geoff Hoon defended Ms Blears, saying she was simply "thinking aloud" about ways to stop community service being seen as a soft option.
It had been very successful in cutting the prison population, he said.
"No-one disagrees with that, but there is a sense that it is an easy ride. All she is suggesting are ways in which it can be seen by the public to be less than an easy ride."
It was important that ministers should have the chance to debate such questions and gauge reaction, he said.
"We have to get respect back in our society."
Tony Blair has made tackling yobbish behaviour and "disrespect" a priority.
The government this week publishes its legislative plans for the next Parliament, which include several measures to crack down on violent crime.
Measures to deal with binge drinking, to give schools the right to search pupils for weapons, and proposals to give community groups and parish councils the power to apply for Anti-Social Behaviour Orders (Asbos) are also expected.