A grandmother is facing unimaginable heartbreak after losing both her daughter and granddaughter at the same time in a devastating highway crash in Queensland.

Kiarra Jesse Bennett, 21, and her two-year-old daughter, Aleyna Ivy Dawn Wallis, were travelling in a freightliner truck driven by Kiarra’s partner, Brodie Wallis, when it collided with a Mercedes-Benz truck on the Bruce Hwy at Canoona, north of Rockhampton, about 10.40pm on Wednesday.

Both Kiarra and little Aleyna died at the scene.

Wallis, 24, was thrown from the truck on impact, suffering extensive injuries and burns.

He was airlifted to a Brisbane hospital in a critical condition, where he remained as of Sunday — still unaware that “his girls are with the angels”.

The 24-year-old driver of the Mercedes-Benz truck suffered minor injuries and was taken to hospital.

Bennett’s mother, Rebecca Bennett, is now enduring every parent’s worst nightmare.

In a heartbreaking tribute shared on social media, Rebecca confirmed the deaths of her “beautiful daughter” and “beautiful granddaughter” with “deepest sadness and a broken heart”.

“They’ve been taken away from us way too soon!! Words cannot express how we’re all feeling,” she wrote.

She also shared prayers for Wallis — Aleyna’s father — and his family as he continues to fight for life.

Rebecca’s friend Kaley Collis, who created a GoFundMe page for the family, said the grief is beyond imagination.

“As a mother myself, I know that losing a child or grandchild, sadly both in this case, is the worst possible thing that could occur for any parent/grandparent,” she said.

“Please donate to help Bec pay for the funerals of these two gorgeous girls on what will be the most horrific day of her life and to also help her and her other three beautiful children with anything else that they may need during this time.”

Police investigations into the cause of the crash are ongoing.