Powers to prevent stalkers from contacting or approaching their victims while police investigate suspected offences come into force on Monday.
The new court order, covering England and Wales, is designed to help police act at “the earliest opportunity”, the government said.
Those who breach the civil order could end up with five years in prison.
Campaigners and victims welcomed the move, but warned the orders would only be effective if police acted swiftly.
From Monday, the police will be able to apply to magistrates for a Stalking Protection Order (SPO), which will usually remain in place for two years.
Courts will also have the power to impose an interim SPO to provide immediate protection for victims while a decision is being made.
The orders will also be able to force stalkers to seek professional help.
Almost one in five women and almost one in 10 men aged 16 and over have experienced some form of stalking, according to the crime survey for England and Wales.
Professor Jane Monckton-Smith, who specialises in researching homicide, stalking and coercive control at the University of Gloucestershire, said: “I think the orders could be really useful if they are used correctly”.
But breaches could put victims in danger and must be taken seriously by the courts, she added. “Stalkers by their nature are obsessive and will keep going and going until they are stopped.”
Plans to introduce the new civil orders were first floated in 2015, when Theresa May was home secretary.
In 2016, then-Home Secretary Amber Rudd promised to introduce them as soon as parliamentary time allowed.
Campaigner Sam Taylor, who runs a victim support group in Sussex, said the orders could give victims “respite” from being relentlessly pursued.
But she said they must be followed by a “significant investment in training” because there was still a “fundamental misunderstanding” in the criminal justice system of what stalking means.
Stalking was made a specific criminal offence in England and Wales in 2012.
In Scotland, stalking is illegal under the Criminal Justice and Licensing (Scotland) Act 2010 and in Northern Ireland it is prohibited under the Protection from Harassment Order (NI) 1997.
Clive Ruggles, of the Alice Ruggles Trust, described the orders as a “powerful new tool”, but said it was “critical” there was no delay in arresting those who breach them.
He said the existence of the orders could have made a “critical difference” for his 24-year-old daughter, who was murdered by her ex-boyfriend.