A first-term National Party MP is seeking cross-party support for a law change for harsher penalties in cases of extreme cruelty to animals.

Tauranga MP Simon Bridges has drafted a private member's bill to raise the maximum penalty for wilful ill-treatment under the Animal Welfare Act from three to five years in prison.

Mr Bridges said tougher penalties for animal abuse were backed by research showing cruelty to animals was an early warning sign of more psychopathic violence later in life.

Murderer Antonie Dixon was an example of this, said Mr Bridges.

"It is time to get tough on really serious animal cruelty. The public's attitude has hardened on this and so should court sentences," said the former Crown prosecutor.

"This is about sending a message that Parliament thinks this offending is abhorrent to our society. It's more than not okay, it's an outrage."

Groups that support the growing call for tougher sentences include the SPCA, the senior lawyers who prosecute cases on behalf of the charity and the Veterinarians Association.

Auckland SPCA executive director Bob Kerridge said the push for change from Mr Bridges sent a strong signal that animal abuse was unacceptable.

"It is time to recognise that cruelty to animals is a social sickness that is as heinous as any act of violence inflicted on fellow humans, and the two are inextricably linked," he said.

Cases of wilful ill-treatment of animals were the most reprehensible acts of cruelty found by the SPCA, he said, and the sentences were abysmally light.

For example, Wayne Williams, 34, was sentenced to four months in jail for beating his partner's dog with a metal pole before strangling it to death.

And Peter James Cooksley, 48, shot a cat with a crossbow bolt through the abdomen for entering his house - but was fined just $500. Mr Kerridge said many acts of animal cruelty were committed by people to torment their partners, including a case where a man was sent to prison for 2 months for throwing three kittens against a wall.

Mr Kerridge said the Auckland SPCA was committed to making sure the public - and the judiciary - were made aware of the serious nature of animal abuse.

"With the support of our remarkable panel of eminent pro-bono prosecutors this will undoubtedly intensify in the New Year," he said.

David Jones QC, a member of the prosecution panel, has said sentences imposed in cases of extreme animal abuse fell considerably short of the maximum penalty.

While the law allowed for sentences of up to three years' jail, the longest sentence imposed was 12 months, which was subsequently reduced to 10.

Actual sentences would increase if the maximum penalty was raised to five years, Mr Jones wrote in the Auckland District Law Society newsletter.

"This would add to the effectiveness of animal welfare legislation and bring home to the public that animal cruelty is not acceptable."

Dr Wayne Ricketts of the Veterinarians Association also backs increasing the maximum penalty for the wilful ill treatment of animals.

Light sentences sent the wrong message to society about the responsibility of humans for the welfare of animals, he wrote last month.

* Going easy

Jailed for four months: Wayne Williams, who beat his partner's dog with a metal pole before strangling it.

Fined $500: Peter James Cooksley, who shot a cat with a crossbow bolt through the stomach.

Source: SPCA