It's currently being debated in NSW parliament and there will be a conscience vote.
Women's rights groups are warning that a New South Wales bill to recognise crimes against unborn children could threaten women's reproductive freedom.
The bill, which is likely to debated in the state parliament next week, is the Crimes Amendment Bill 2013 - also known as Zoe's Law.
The amendment would - for the first time in Australia - recognise a crime of grievous bodily harm against an unborn child.
Zoe's law is so named after the stillborn child of New South Wales mother Brodie Donegan, who on Christmas Day 2009 was struck by a car as she walked down the street.
The injuries suffered by Ms Donegan resulted in the death of her fetus at 32 weeks gestation, but the driver was not charged with Zoe's death because the law did not recognise her as a person.
Mr Spence says the bill stipulates that the offence will not apply to medical procedures or to conduct engaged in with the consent of the mother.
"It is absolutely explicit that medical procedures are exempt and that anything done by or with the consent of the mother, it is absolutely nothing to do with abortion laws nor will it have any influence on them."
Chair of the national Women's Electoral Lobby Melanie Fernandez says the established law is enough to ensure that crimes against a fetus are punished.
"The concern that the women's sector has is that this bill establishes personhood for a fetus so it defines a fetus as a living person from 20 weeks or from 400 grams and so the concern that we have is that this legislation is being used to set precedent to then bring further legisation that rolls backs women's access to abortion and productive rights."
Currently across Australia, a fetus has no legal rights and is not considered to be a person.
However in several jurisdictions, a person can be charged with grevious bodily harm against a woman that results in the death of a fetus, but they cannot be charged with a crime against the fetus itself.