Tens of thousands of victims are being let down by a criminal justice system which fails to recognise stalkers, campaigners have said.
Only offenders whose behaviour escalates to violence are handed substantial jail terms, leaving victims suffering years of abuse, and a new stalking law needs to be brought in to tackle the problem earlier, the probation union Napo said.
The call comes as shadow home secretary Yvette Cooper committed the Opposition to the move in a speech to Labour women gathering for the party's annual conference.
She blamed a "lack of clarity" in the law for allowing stalking cases to escalate into still more "heinous" crimes against both women and men.
Some 120,000 victims, mostly women, are stalked each year, but just 53,000 are recorded as crimes by police and only one in 50 of these lead to an offender being jailed, Napo said.
Harry Fletcher, the union's assistant general secretary, added: "Unless stalking laws are reformed and therefore treated seriously, women will continue to be assaulted, psychologically harmed and even murdered."
Last week, an unemployed 22-year-old man from Nottingham who stalked his girlfriend online for years without her knowing it was him admitted causing harassment when he appeared before magistrates.
Ruth Jeffery, 22, said Shane Webber, who faces up to five years in jail when he is sentenced next month, had "wrecked the past three-and-a-half years of my life".
Laura Richards, a psychologist with Protection Against Stalking, said: "Too often the pattern of stalking behaviour and the escalation is missed by professionals.
"The psychological terror and fear goes unrecognised. Incidents tend to be seen in isolation and it is only when the most serious assaults happen that it is taken seriously, but by then it is all too late."