A South Australian man who inflicted "quite shocking" injuries by repeatedly smacking two young children when they would not sleep has escaped jail.
Jake McKenna, 22, of Whyalla, left the two-year-old girl and one-year-old boy with bruising to their buttocks, thighs and hands before his arrest in November 2017.
In sentencing, District Court Judge Gordon Barrett said McKenna was in a relationship with the children's mother when authorities were alerted to the children's injuries.
"The authorities visited your house and saw what were really quite shocking injuries to both children," he said.
McKenna admitted he smacked both children on the buttocks when they would not go to sleep and, when their buttocks were too sore, he smacked them on the backs of their hands.
There were also injuries on the children's heads and faces, but those were not factored into McKenna's sentence.
Judge Barrett said some of the bruising was caused while the "vulnerable and very young" children were wearing nappies.
"It must have been plain to you that they were injured when you were hitting them," he said.
"Your hitting must have been repeated and forceful to cause such extensive bruising."
He said the two children had been physically and emotionally harmed by McKenna's actions.
His partner - the children's mother - was described by Judge Barrett as "by no means an adequate carer for the children", who have since been removed from her care.
Both were heavy drug users in the lead-up to the arrest, while McKenna was also suffering an untreated mental illness.
He pleaded guilty to two charges of aggravated causing harm with intent, and has already spent a month in prison and more than three months on home detention bail .
Judge Barrett said he accepted McKenna was "truly remorseful" and handed him a wholly suspended non-parole period of one year, nine months.