DNA testing has saved a dog accused of attacking a woman on the NSW north coast from death row.

Des Schroder, from the Clarence Valley Council, said the woman suffered bite wounds when she was attacked at South Grafton in April.

He said the victim later identified her attacker from a photo line up, but DNA swabs sent to a lab in Victoria told a different story.

Mr Schroder said in the past the dog may have been put down.

"Absolutely because we take attacks really seriously and quite often one of the outcomes for that dog is if they are attacking people they are put down," he said.

"Obviously it's very important to get the right animal.

"It hasn't been used in the past, because DNA sampling was very expensive, but it's come way down in price and it [has now] become feasible to use.

"Especially when we've got some confusion about which dog did do the attack, and it turned out one of the dogs which was highly suspected wasn't the animal and that's obviously got implications for the people that own that animal.

"So now we know that we're looking for a different dog."

Mr Schroder said testing indicated the dog responsible for the attack was a dark-coloured Great Dane cross.