Barrister Ron Mansf' />

A legal expert says at present police have to prove "murderous intent" to win cases against drivers who kill unborn children.

Barrister Ron Mansfield said as the driver accused of drink-driving causing death in Ann-Maree Hardiman's case could not have known she was pregnant, charging him with the death of the unborn child was pointless.

"In this case, he can't be charged," he said.

"So it's not likely to apply to a motor vehicle accident where you don't know who is in the car."

Mansfield said as far as the Crimes Act was concerned embryos were not recognised as a human being until they were born.

He added, though, that the death of the child would be recognised by judges.

"Any physical and emotional loss - and the fact the pregnant mother died - would be an aggravating factor at sentencing."

Hardiman's grieving partner Ron Blackaby has called for a law change to prosecute drink drivers who kill unborn children.