In the care of her father for the first time, a whining and bawling toddler needed "reassurance and encouragement," a provincial court judge said Tuesday.

Instead, father Stanley Okeh slapped his three-year-old daughter twice on the thigh and once more on her back, leaving red marks obvious the next day to her mother and police, as well as doctors at Royal Inland Hospital.

Okeh was convicted of the lesser charge of assault by judge Stella Frame, who ruled the red marks that disappeared after a few days can't fulfil the original charge of assault causing bodily harm.

"It defies explanation what could possibly be achieved by spanking a three-year-old child who is upset and needing her mother," Frame said in a written decision.

"This is a situation that demands reassurance and encouragement. Instead, the girl received a hard spank to the thighs which left her marked for several hours at the very least."

The events occurred the evening of July 26 last year. The mother left her daughter in the care of Okeh for the first time. The two did not live together; Okeh, a Nigerian student at Thompson Rivers University, saw her every week or two and had never cared for the girl overnight.

The science student testified that he spanked the girl to correct her after she fussed and tried to escape from him with a soiled bottom. He had been awakened and was suffering from a lack of sleep.

He said in court that he struck the girl on the back as he tried to press her to the floor as she flipped over to escape.

"This is an entirely different characterization from what he texted to (the mother) and what he told (RCMP) Const. Wood," Frame said.

The girl's mother noticed the red marks on her daughter the next day. She texted Okeh, asking him what happened.

He responded "she haz to learn gud frm young."

The mother shot back "not like that, that will never happen again."

Okeh will be sentenced at a later date.

Defence lawyer Sheldon Tate argued unsuccessfully that the hit to the girl's back was an accident as Okeh tried to stop her from escaping.

"I find this was not an attempt by Mr. Okeh to pin (the girl) to the floor but was a spank precipitated by frustration born of Mr. Okeh's exhaustion, the time of night, the child's whining and her attempts to wiggle away from him."

Tate also argued that, as a father, Okeh had rights as set out in the Criminal Code to use corporal punishment when he slapped his daughter on the thigh.

But Frame rejected that argument, ruling Okeh did not have the authority to hand out corporal punishment. And even if he did, the force was excessive.

While he is the girl's biological father, her mother "reserved the parenting rights to herself, very specifically and clearly. . . . She did not authorize the type or extent of discipline he used."