A Saskatchewan woman has pleaded guilty to impaired driving causing death after three people were killed in a collision involving a pickup truck and a road grader.

Stephanie Lorrin McNab of the George Gordon First Nation has also pleaded guilty to impaired driving causing bodily harm for the May 2014 collision.

Court heard that a truck carrying three men and three women slammed into the back of the grader on a grid road south of Punnichy.

Two men, a 37-year-old from Sandy Bay and a 47-year-old from the same First Nation, died at the scene.

A 30-year-old woman died en route to hospital, while the grader operator suffered minor injuries.

A sentencing hearing has been scheduled for June 16.