A drunk driver who killed three children and their grandfather in a horrific crash north of Toronto is set to be sentenced today.

Marco Muzzo, 29, pleaded guilty last month to four counts of impaired driving causing death and two of impaired driving causing bodily harm.

Prosecutors are asking for a sentence of 10 to 12 years behind bars and a ban on driving for eight to 10.

The defence has argued an eight-year sentence would be enough, with credit for the four months he has already spent in custody.

Nine-year-old Daniel Neville-Lake, his five-year-old brother Harrison, their two-year-old sister Milly and the children's 65-year-old grandfather, Gary Neville, died last September after the van they were in was hit by a speeding Muzzo, who was driving an SUV.

Muzzo told the court last month that he would forever be haunted by the grief and pain he has caused the Neville-Lake family.

But the children's parents, Jennifer and Edward Neville-Lake, left the courtroom while he spoke and later said they had no interest in what he had to say.

Jennifer Neville-Lake previously said the death of her children and father has shattered her world.

Court has heard Muzzo was returning from his bachelor party in Florida on a private plane and picked up his car at Pearson International Airport.

Breathalyzer tests showed he had between two and three times the legal amount of alcohol in his blood.