Warning: Disturbing content

A police officer accused of "inflicting violence and terror" on his family for years and making his ex-wife fear for her life is standing trial in Auckland.

The Crown alleges the officer bragged about giving his nephew "a hiding" in the back of a police car, forced his stepson to say he had sex with a cat and grabbed his ex-wife by her hair and pushed her face into the ground, among a raft of family violence allegations.

The man denies seven charges relating to his former wife, former stepson and nephew, some dating back as long as 18 years ago.

"He had a dark, unpredictable mood," said Crown prosecutor Jo Murdoch.

"He was cruel not only to [his ex-wife] but to her young son who became the defendant's stepson in those formative years.

"He was overbearing and violent to his nephew, who at a young age began to have run-ins with the law."

Alleged psychological and physical abuse against his former stepson made him a "select mute", withdrawn and he did not want physical touch.

"This type of conduct towards [the complainant] repeatedly over a long period of time is what [the] Crown alleges ... amounts to child cruelty," said Murdoch.

The tipping point for his ex-wife to lay a formal complaint was when her young son, also the son of the defendant, witnessed the abuse and asked his mum to call the police, Murdoch said.

She made complaints to police in 2009 but no charges were laid then. She raised them again in 2017.

Defence counsel Mark Ryan suggests his client's ex-wife only flagged her 2009 formal complaints in 2017 because she was going through a custody battle with the defendant over their son.

"The old tit-for-tat regime and [she] goes back to police and says: 'I need to reignite these complaints from years ago'.

"Thou have no fury like a woman's scorn."

Ryan told jurors New Zealand has a "terrible history record of domestic violence" but that shouldn't mean they "automatically" find him guilty.

Ryan said it was "flawed thinking" to assume the male is always the aggressor.

"He has consistently denied being the aggressor ... in a volatile relationship," said Ryan.

The police officer and all complainants have name suppression.

A jury of four men and eight women has been selected at Auckland District Court this morning.

The officer denies two counts of injuring with intent to injure, three counts of assaulting with intent to injure, one count of injuring with reckless disregard and one count of child cruelty.

The trial is set down for three weeks before Judge Pippa Sinclair.

The Crown is calling eight witnesses, some of whom are giving evidence from behind a screen.

Where to go for help or more information

• Women's Refuge: Free national crisis line operates 24/7 - 0800 REFUGE or 0800 733 843
• Shine, free national helpline 9am- 11pm every day - 0508 744 633
• It's Not Ok: Information line 0800 456 450 www.areyouok.org.nz
• Shakti: Providing specialist cultural services for African, Asian and Middle Eastern women and their children. Crisis line 24/7 0800 742 584
• Ministry of Justice: www.justice.govt.nz/family-justice/domestic-violence
• National Network of Stopping Violence: www.nnsvs.org.nz
• White Ribbon: Aiming to eliminate men's violence towards women www.whiteribbon.org.nz

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