The man on trial for murdering his 2-year-old stepdaughter told police he was "110 per cent" innocent and her death left him heartbroken.

Michael Joseph Martin, 25, has pleaded not guilty to murdering Leilani Mary-Jane Lotonu'u at their Manurewa home in June 2012.

He is accused of hitting the little girl so hard an internal organ ruptured, resulting in a fatal infection.

The defence says Martin is innocent and the child's mother Amy Lorigan must be responsible.


On the seventh day of Martin's trial in the High Court at Auckland today, the jury was shown a DVD of him being interviewed by police shortly after the death.

Martin proclaimed his innocence and said he would never do anything to harm a 2-year-old.

He said he didn't seem worried because he knew he wasn't responsible for Leilani's fatal injuries.

"Our hearts have been broken. We've had two days of not eating well [and] a lot of cries. All these cries have made me stronger," Martin said.

"I want to get to the bottom of why she passed away because we're the ones that are suffering a loss.

"I don't think anyone could kick or punch or use a weapon on a 2-year-old 110 per cent it wasn't me."

A tearful Martin said he would explain the injuries if he could.

"I can answer any questions yous have to me, 100 per cent. I'd do anything for this little girl."

Leilani was pronounced dead shortly before 6am on June 10, 2012, when paramedics were unable to save her.

The day before, Martin and Ms Lorigan were looking after the little girl but she was alone with Martin for about an hour when Ms Lorigan went grocery shopping.

Martin has also pleaded not guilty to a charge of child neglect for failing to provide Leilani with medical assistance.

The trial continues.