Robberies involving knives have risen by 72% to 42,020 attacks across England and Wales in the last year, according to a report by an independent charity.
Thousands of knives were handed in during a June amnesty
A study carried out by the Centre for Crime and Justice Studies (CCJS) describes government strategy on tackling knife crime as "incoherent".
The Home Office said British Crime Survey figures to March 2006 pre-dated the knife amnesty, which began in May.
The CCJS claimed knife amnesties have a "negligible" impact on knife crime.
The report - carried out by the charity, which is based at Kings College, London - also found insufficient evidence to show amnesties or tougher sentences reduced the numbers carrying or using knives.
The study comes weeks after more than 100,000 weapons were handed to police in England, Scotland and Wales during a national knife amnesty.
During the five-week amnesty, which ended on 30 June, people could dispose of knives in secure bins without being prosecuted for possession.
Chris Eades, author of the CCJS report, said: "Not enough is known about the carrying and use of knives or why people engage in those activities.
"Consequently, the government is constructing responses without any credible evidence that they will be successful.
"Knife amnesties will have a negligible impact since knives will be available as long as there is unsliced bread.
"If the goal of criminal justice policy is to reduce the number of victims and the harm they suffer, we should look at the root causes - the inclination or desire to resort to violence."
Official statistics show violent knife crime in England and Wales has dropped in the last 10 years.
HOME OFFICE FIGURES*
Violent crime in 1995 4,256,000
Violent crime 2005/6 2,420,000
Violent crime involving knives in 1995 340,480
Violent crime involving knives 2005/6 169,400
Robbery involving knives 2004/5 24,290
Robbery involving knives 2005/6 42,020
*England and Wales only
Mugging and robbery involving knives has "significantly" decreased from figures collated in 1995 - 29% to 13%.
A Home Office spokesman said there was evidence to suggest that robbery involving knives may be fuelled by the number of gadgets such as mobiles that people carry.
But the CCJS said the limitations of official statistics made it impossible to conclude that "the overall use of knives in crime is declining".
The study - entitled: "Knife Crime: Ineffective reactions to a distracting problem" - also highlighted that there was limited research on why people carry knives.
But it noted that children who have been a victim of crime may be more likely to carry knives.
MUGGINGS/ ROBBERIES (BRITISH CRIME SURVEY FIGURES)
Figures for England and Wales only
The research also showed children, young people, those living in poor areas and members of black and minority ethnic communities were more likely to be the victims of knife crime.
A Home Office spokesman said: "The recent knife amnesty took almost 90,000 knives out of circulation in England and Wales.
"We will increase the maximum sentence for carrying a knife in public without good reason from two to four years, to give a clear message that knife carrying is a serious matter which can attract a long custodial sentence."
The government is also planning to raise the age limit for buying a knife from 16 to 18 and give head teachers the power to search pupils for dangerous weapons.