A law expert says it was assault when a senior police officer hit his children with a belt. 

The Independent Police Conduct Authority has found the North Island officer struck his three children multiple times, on their lower body.

He admitted using his belt to 're-set' his kids - and has been censured by police for serious misconduct.

Auckland University law professor Mark Henaghan says criminal proceedings couldn't go ahead because neither the parent or children would give evidence.

"Liz Gunn just taps someone on the shoulder and gets charged with assault - this is hitting kids with a belt and nothing has happened." 

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