Warren James Ross accused of murdering two-year-old Tanilla Warrick-Deaves was declared guilty by a jury in the NSW Supreme Court on Thursday afternoon. The jury handed down its verdict in the Supreme Court in Sydney after a day-and-a-half of deliberations. In its ruling the jury said that the 30-year-old Mr Ross had relentlessly beaten the two-year-old girl, daughter of his then-girlfriend Donna Deaves, at her Watanobbi home on the NSW central coast in August 2011, leading to her death. He will now face a sentence hearing at a later date.

The courtroom saw several emotional outbursts as the verdict was read out.

Once the verdict was announced, Mr Ross started abusing a member of the public gallery who was sitting next to his mother even as several people in the public gallery shouted: "Yes!"

He pointed out to the man sitting next to his mother and said, "You want to "f...ing get away from my mother" and "I don't f...ing care what I say any more."

Mr Ross' mother, Sue Patterson who was in the public gallery, wept and told her son, "I love you."

Responding to her, Mr Ross replied, "It's all right, mum" and "It's not over." Mr Ross is also reported to have called a female member of the media a "c..."

Media reports say, as Justice Stephen Rothman read out the report, one member of the jury wept and others were visibly distressed.

Thanking the jury for their services, Justice Rothman said the member would be offered counselling after going through such a distressing case.

The prosecution case said Mr Ross had been going out with Tanilla's mother, Ms Deaves, for a couple of months when he decided to toilet train the toddler. In the process he subjected her to prolonged horrific physical abuse.

Several witnesses in the case which included the couple's neighbours told the court about hearing Tanilla's screams as she was punished by her mother's boyfriend, even as her mother watched on.

He would force her to run laps, hit her and whipped her with various implements the prosecution said. He would also beat the child with an electric cord and his belt and deliberately dropped a heavy toolbox on her tiny hand.

Ms Deaves, too turned witness in the case, told the court she watched as her former boyfriend inflicted the fatal injuries on her daughter on August 25, 2011.

He banged the toddler's head on a glass shower screen, holding her upside down over the toilet bowl and causing her to slam her head against a cupboard door.

"I tried to stop it," Ms Deaves told the court.

"I tried. I couldn't handle it," she said

Over the next two days, Tanilla was left in her pram before Ms Deaves discovered she wasn't breathing and called triple zero.

During the six-week trial, Mr Ross is allegedly to have threatened Ms Deaves, who received a reduced sentence in return for giving evidence against her former boyfriend.

Tanilla's biological father, Adrian Warrick, was in court to hear the verdict in which Mr Ross pleaded not guilty.

Mr Ross will now face a sentence hearing at a later date.