A law taking effect today will make it a crime to use repeated threats, humiliation and intimidation to control people.
It will mean that "coercive or controlling" behavior can be seen as domestic abuse and can be prosecuted as a crime punishable by up to five years in prison.
Authorities say stopping someone from socializing, controlling their social media access or using apps to put them under surveillance will in some cases be covered by the new legislation.
Making threats to publish personal information can also be viewed as a crime. Director of Public Prosecutions Alison Saunders says this type of behavior "can limit victims' basic human rights" by reducing their freedom of movement and their independence.
"This behavior 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 behavior might seem playful, innocuous or loving," she said.
"Victims can be frightened of the repercussions of not abiding by someone else's rules. Often they fear that violence will be used against them, or suffer from extreme psychological and emotional abuse."
Many victims say the trauma from psychological abuse is worse than the trauma of physical abuse, Saunders said.
The new legislation was created after a majority of people consulted by the government said that existing laws on abuse did not offer sufficient protection. It is supposed to apply only in cases where the offending behavior is repeated or chronic.