New laws threatening five years jail time for driving while "avoidably distracted" come into force on Monday.
Previously the maximum sentence for those convicted of causing death by careless, uninsured or unlicensed driving was a maximum £5000 fine and penalty licence points.
The new laws follow advice from independent Sentencing Guidelines Council last month and include drivers using mobile phones - calling or texting - drinking or eating and applying makeup.
The new offences will, for the first time, allow courts to imprison drivers who cause deaths by not paying due care to the road, or to other road users.
They are designed to plug the gap in current legislation and prevent drivers who kill walking away from court with just a fine.
"Drivers who kill through carelessness will no longer be able to walk away from court with just a fine," said justice minister Maria Eagle.
"Neither should uninsured or unlicensed drivers who deliberately flout the law.
"Driving requires full concentration at all times. A moment's distraction can make the difference between life and death."
Mick Giannasi, Gwent police deputy chief constable and Acpo spokesman on roads policing, added: "Careless drivers put themselves and others at risk every time they get behind the wheel of a car.
"The introduction of this legislation will hit home the message that driving is a hazardous activity that requires total concentration. Allowing distractions to affect your standard of driving is not acceptable and will now be more appropriately punished under the law."