Baby's father denies causing bruises

A Queensland man accused of abusing his baby son says he has no idea how the child became bruised and battered during a weekend visit.

The 25-year-old man from southeast Queensland is on trial charged with assaulting his 11-month-old son last June.

The infant was found with two broken bones, a large burn to his face and large bruises after staying the weekend at his father's house southeast of Brisbane, the trial has heard.

A video recording of the accused being interviewed by police was played to the jury in the Brisbane District Court on Wednesday.

The man, who's also been charged with child cruelty, told detectives he'd inadvertently given his son a bottle of formula that was too hot.

"I didn't realise it was too hot and that's when (my son) got burned," he said.

"When I realised I took the bottle off him. I honestly don't know how it happened."

The man said he began applying ice to his son's face and "after that he seemed OK".

The father of two also told police he only noticed his son's bruises when he got him out of his cot on the Sunday morning.

"I don't know how those bruises happened, whether he's tried to climb out of his cot or something, I wasn't sure," he said.

The man told the child's mother via Facebook about the burn and bruises and she "flipped out", he said.

The trial continues.