An Auckland woman has denied failing to protect two young girls against assaults from another person who used a hammer and toy train, and one girl from sexual assault. 

The woman, who has interim name suppression, was charged last week with five historical counts of child abuse, dating back as early as 2009. 

She was also charged with leaving a child under the age 14 without supervision on January 12. 

She pleaded not guilty to all six charges today at Auckland District Court through her lawyer, and via audio-visual link. She was aided by a Tongan interpreter. 

The woman, 44, elected a trial by jury, and has been remanded in custody until a bail application hearing in February. 

Judge Claire Ryan told the interpreter and the woman that she wanted to convey her "concern and sorrow about what's happened in Tonga", after a volcano eruption triggered a tsunami on Saturday. 

"I have friends in this country and in Tonga and I share the concern and worry which I'm sure is much more acutely felt in Tonga," Judge Ryan said. 

The woman could be seen nodding in response, but otherwise showed no emotion throughout the hearing. 

Her historical charges include two counts of failing to protect a girl who she knew to be at risk of sexual assault between 2015 and 2016 and between 2012 and 2018. 

Additionally, the woman is accused of failing in 2014 to protect the same girl at risk of sexual assault, from being assaulted with a hammer, and of wounding the same girl herself in 2019. 

She is also accused of failing to protect another young girl from assault with a toy train, by another person between 2012 and 2017. 

She was arrested alongside a man who faces 15 charges, including six counts of assaulting or injuring one of the children between 2010 and 2018 and an additional count of injuring the other child. 

The child who he is accused of having focused the brunt of his aggression on is also the focus of eight counts in which the man is accused of molestation. 

He could face up to 20 years in prison if convicted of sexual violation. 

He was also granted interim name suppression last week and is due to next appear at Auckland District Court on Friday. 

- by Miriam Burrell with additional reporting by Craig Kapitan