Domestic abusers who control their victims using social media or spy on them online could face up to five years behind bars from Tuesday.
Offenders who use repeated "controlling or coercive behaviour" to cause serious psychological and emotional torment for spouses, partners and other family members could now face criminal charges.
The Crown Prosecution Service said the type of abuse covered by the new law could include a pattern of threats, humiliation and intimidation or stopping someone from socialising, controlling their social media accounts, surveillance through apps and dictating what they wear.
Director of Public Prosecutions Alison Saunders said: "This behaviour can be incredibly harmful in an abusive relationship where one person holds more power than the other, even if on the face of it this behaviour might seem playful, innocuous or loving.
"Being subjected to repeated humiliation, intimidation or subordination can be as harmful as physical abuse, with many victims stating that trauma from psychological abuse had a more lasting impact than physical abuse.
"These new powers mean this behaviour, which is particularly relevant to cases of domestic abuse, can now be prosecuted in its own right."
Polly Neate, chief executive of Women's Aid, said it was a "landmark moment" in the approach to domestic abuse.
The new powers were introduced after concerns that the previous legislation did not protect victims enough.
Home Office guidance says that in order for the offence to apply the pattern of behaviour alleged must have a "serious effect" on the victim.
Police and prosecutors are being trained to recognise patterns of behaviour which meet the criminal threshold.
Earlier this month police watchdogs revealed there has been a "staggering" increase in reports of domestic abuse, with recorded crimes jumping by almost a third in less than two years.