No sentence would be enough to ''bring our Ruby back'', the Marris family said after the tourist responsible for the 5-year-old's death was jailed for 18 months.

Ruby Jay Marris was killed when Chinese national Jing Cao (32) crossed the centre line in his rented Ford Ranger on State Highway 1 near Moeraki on February 21, and smashed into the Marris family's station wagon.

Following Cao's emotional sentencing in the Dunedin District Court yesterday, Ruby's parents Tristan and Kimberley told media the Government needed to toughen regulations around the leasing of rental cars.

Jing Cao in the dock at the Dunedin District Court during sentencing yesterday.

''Today Mr Cao has received his sentence, but it doesn't matter what it is, as nothing will bring our Ruby back,'' a statement from the couple said.

''This was an unnecessary accident and the New Zealand Government needs to regulate the hiring and licensing of all rental vehicles to overseas tourists.

''We do not want any more families to have to go through the pain and suffering we have been through. Urgent action needs to be taken.''

Cao was jailed for 18 months by Judge Kevin Phillips for dangerous driving causing the death of Ruby and was given nine months' jail on each count of dangerous driving causing injury to the other four occupants of the Marris family's car and his own mother, a passenger in his rented vehicle.

The sentences will be served concurrently.

Judge Phillips also ordered Cao to pay $27,500 emotional harm reparation to the Marris family and further reparations of $34,390.

Earlier, the court heard Mr Marris' victim impact statement.

He placed a photograph of Ruby in front of Cao before detailing how the tourist had ''cut short such a wee, beautiful girl's life''.

The family were returning to their Oamaru home after an ''exciting'' day shopping when Mr Marris came over the brow of a hill near Moeraki about 4.50pm and found a car driving towards them on the wrong side of the road.

Cao had travelled more than 1300km after arriving in Auckland on February 17 with his partner and parents.

He hired the Ford Ranger in Auckland to tour New Zealand.

Cao spent the night of February 20 in Christchurch and left about 10am to travel to Dunedin.

After stopping at the Moeraki Boulders to take photographs, Cao drove the four-wheel-drive on to State Highway 1 and about 450m down the road crossed the centre line. He travelled about another 450m before ploughing into the Marris family's car.

Ruby died at the scene and Mr and Mrs Marris suffered serious injuries.

The Marris' two other children, Georgia (9) and Sophie (7), suffered moderate injuries.

The injured family members were taken to Dunedin Hospital.

''I wake up thinking about her. I go to bed thinking about her and the guilt you have caused me because it was my idea to go down to Dunedin to shop that day,'' Mr Marris told Cao - who was accompanied by a Mandarin translator - in court.

''I know you can't understand me, but you can tell the expression on my face and the emotion in my voice as I read this to you.''

At times, Mr Marris sobbed and, at one point, stomped his feet in anguish while reading out his statement.

''You were doing something with your phone, people were seriously hurt and crying around you,'' he said, recounting the moments after the crash.

''I could see Kimberley holding Ruby screaming, 'Somebody help'. I could see Ruby getting paler and paler as her internal injuries were starting to take effect and the blood was draining from her body.''

The death of their ''wee angel'' had left the family heartbroken, he said.

''There was no remorse from you that day,'' Mr Marris said to Cao.

''You were probably in shock, but there were people dying from your actions.

''I got told Ruby died, while lying on the road. You would have heard me scream. It took three people to hold me down with a broken back.

''I can't understand how you could blatantly ignore the most important road rule in New Zealand - to keep left.''

Cao's assertion he was tired was a ''feeble excuse'', Mr Marris said.

''She was only 5, Mr Cao.''

''Burying Ruby 11 days after the accident was the worst day of my life - the funeral was indescribable.

''Words can't describe what it's like burying your own daughter.

''I know you didn't set out to kill someone that day, but you did.

''You have to live with this for the rest of your life.''

Cao - who was dressed all in black and hung his head throughout most of his sentencing - offered an apology to the family.

''He would like to first offer his sincere apology to your family,'' Cao's translator said to family members sitting in the public gallery of the court, as Cao bowed three times.

''He understands that what he has done with the accident has caused deep harm and loss to your family that are not compensatable.

''Since the day of the accident, he has been self-reflecting and blaming himself for what he has done and he understands he will never be forgiven by your family and he can't forgive himself, as well.''

Cao owed the family his life, the translator said, before Cao told the family in English: ''I'm sorry. Really, really sorry'' and then bowed three times more.

Judge Phillips took a starting point of three years and three months' jail.

He reduced the sentence for Cao's early guilty plea, extreme remorse, good character, reparations and the undue hardship prison provided for non-English speaking foreign nationals.

Cao was also disqualified from driving for four years.

He had no previous convictions.

After Cao's sentencing, the Marris family thanked the members of the public, emergency services and medical staff who provided the family care on the day of the crash and the months that followed.

''We were astounded by the incredible support, generosity and love we received from Oamaru and the whole of New Zealand,'' the family said.