An inquest has heard more criticism of how police handled a domestic violence case which ended in murder.

The coroner has been told two phone calls were made for South Australian police assistance but the operator failed to act appropriately.

A senior police officer has defended using civilians rather than officers to staff the line.

The court was played a call answered by police assistance line operator Kellie Van Dongen, 10 months before Zahra Abrahimzadeh was stabbed to death by her estranged husband.

Ms Van Dongen answered two calls seeking help, one from the victim's son, the other from a domestic violence worker.

The operator did not arrange to send a patrol, instead transferring the call to police at Port Adelaide.

The inquest was told that was one of a number of mistakes Ms Van Dongen made.

Mrs Abrahimzadeh's son Arman called about half an hour later seeking help but was told: "Because your mum has taken a restraining order out against your dad, he hasn't technically broken that restraining order."

Ms Van Dongen was wrong to give out that legal advice, Superintendent Bruce James-Martin, who used to manage the call centre, told the coroner but he defended the civilian call centre operators.

He said that said while Ms Van Dongen had made a number of errors, the system generally worked.

He said the operators did an exceptionally good job and there was no reason they could not perform their function as well as police officers.

Unlike triple-0, the assistance line deals mainly with matters which are not urgent.

Superintendent James-Martin said the assistance line tried to roster two supervising officers for about a dozen operators and he denied the service was under-resourced.

But he said operators now received better domestic violence training.

Zialloh Abrahimzadeh was jailed for stabbing his estranged wife to death at the Adelaide Convention Centre in 2010, in front of a horrified crowd of hundreds of people.