A YOUNG mother who murdered her toddler son by leaving to drown at Hillarys Boat Harbour has been jailed for life with a 13-year minimum before she is eligible to be released.

Gemma Gaye Killeen, 23, was sentenced to life imprisonment after admitting abandoning her 22-month-old son Te Reringa Kayden Wetere at the marina in November 25, 2010, but denied she intended to kill him.

The sentence was backdated to when she was arrested shortly after her son's death, which means she will be behind bars till at least November 2023, when she will be 35.

She pleaded guilty to murder, sparing both families the trauma of a trial, but claimed she never meant to hurt her son.

Earlier this week, the Supreme Court was told Killeen abandoned her toddler, known as Kayden, in a bid to grab the attention of her on-and-off again partner Eddie Wetere.

Supreme Court Justice Stephen Hall today described Killeen as a “selfish” and “self-absorbed” young woman who was motivated by a desire to create a “drama” as part of a desperate bid to win the attention of Mr Wetere.

He said that while he concluded that her actions were impulsive and stemmed from anger, her subsequent behaviour, by claiming Kayden had been abducted, then directing search efforts in the wrong area, was deliberate.

He also said she failed as a parent in the most important duty – to protect her son from harm.

Killeen drove to the north car park of Hillary’s Boat Harbour and placed her son by the water’s edge before driving off to the south side car park and made false claims that Kayden had been abducted. Despite knowing where her son was, she never directed search efforts towards the north car park.

“You placed him by the water's edge which is seriously aggravating,” Justice Hall said. “You remained there in the car park for a further two minutes. You left him in life-threatening danger.

“There were moments in which you could have saved your son.

“Even if your judgment was clouded by anger, it was in those moments that you could have changed the course of the outcome.

“That you could do such a thing to a 22-month-old child only beggars belief.

“As a parent it is your duty to care and protect him from harm. He trusted you to care for him.

“It’s difficult to understand the confusion and fear (he would have felt) when he realised he had been left alone.”

Earlier this week the Supreme Court was told on the day in question, Killeen had sunbathed at her mother’s home then went shopping and had even got a manicure.

By late afternoon she attempted to contact Kayden’s father, who she had an argument with the night before, however he failed to return her calls and text messages. It was then that she decided to do the unthinkable.

After she placed Kayden by the water, she called Mr Wetere’s mother who did not answer then called her own mother, claiming she had lost her son.

Her mother Sheryl immediately rushed to her daughter's side to help with the search. But sadly little Kayden was found face down in the water by a couple passing by 6.25pm.

Justice Hall said he accepted Killeen never intended to kill Kayden but was unable to conclude that a life sentence would be unjust due to the “serious aggravating” circumstances of Killeen's horrific crime.

He said that while her lawyer had submitted a report which said she was in an emotional state at the time, it did not indicate that she suffered any mental illness.

And he said because she never intended to kill Kayden, it was difficult to understand why she did it, and could only conclude that her motivation was driven by her selfishness and a desire “to get attention by creating a drama”.