A senior police officer is calling on the government to review whether laws governing cyber-stalking in the UK are fit for purpose.
Greater Manchester Assistant Chief Constable Garry Shewan wants police to be given more powers to seize computers used to harass victims online.
It is hard to prove who committed stalking even though it is easy to establish which computer was used.
The Home Office says it is investigating the issue.
Mr Shewan, who is the Association of Chief Police Officers (Acpo) leader on the issue of stalking and harassment, met ministers at the Home Office last week.
He said: "The legislation is 12 years old and I don't think anyone envisaged 12 years ago the extent that the world wide web would open up opportunities to harass and stalk people via the internet."
Cyber-stalkers can currently either be charged under the Protection from Harassment Act or the Malicious Communications Act, but charities and academics say neither is sufficient given the expansion in technology in recent years.
As the number of people using computers has increased, so has the ability to tap into personal information online.
Mr Shewan wants it to be easier to seize computer equipment from a suspect and to get internet providers to hand over the IP address, which can be used to trace the suspect.
Professor Carsten Maple, who heads the National Centre for Cyber-stalking Research at Bedfordshire University, said it was easy for those in-the-know to track down information.
He said Trojan spyware can be used to hack into anybody's computer, access their personal files and even secretly switch on their webcam.
Trojans are viruses which pose as harmless programmes and can be sent into computers via e-mails and other methods.
Yet currently police find it difficult to seize computer equipment unless they can prove there was an intention to cause fear or distress.
Prof Maple added his voice to calls for a review of the legislation.
He said: "The lack of power to seize computers makes it difficult to prove who is responsible for stalking, even if it can be shown beyond reasonable doubt that a particular device was used to commit a crime."
Jane Harvey from the Network for Surviving Stalking said 77% of stalking victims waited until more than 100 incidents had happened before going to the police.
She said when they finally took that step it was vital their allegations were taken seriously and the situation investigated fully.
"This is a devastating crime - being stalked online can ruin people's lives," she said.
"We urge the government and the police to do everything possible to ensure those affected by cyber-stalking get proper access to justice."
Prosecutions under the Malicious Communications Act have soared to an all-time high and increased almost 300% in five years to 899 last year.
Charges under the Protection from Harassment Act have risen from just under 12,000 to 12,549 in five years.
Separate figures from the Crown Prosecution Service (CPS) show that last year 33% of stalking incidents were by e-mail, 32% by text message and another 8.4% through social networking sites.
A Home Office spokesman said it was working with the police, Crown Prosecution Service and charities to try to improve the police response and make sure there were robust prosecutions.
He said: "Cyber stalking is a crime. As with all other forms of stalking we take it very seriously and we expect other agencies to do the same.
"The Home Office, Ministry of Justice and the Crown Prosecution Service are currently working together with victims and support charities to discuss whether the Protection from Harassment Act 1997 and its enforcement has been effective in providing an appropriate response to stalking."