Opponents of greyhound racing in South Australia have said exposing data on the sport would support a case for a local ban.

New South Wales is set to become the first Australian state to ban greyhound racing after animal cruelty was uncovered in the local industry, including mass greyhound killings and live baiting.

Tania Noble from the Animal Justice Party said they had been told the adoption rate for dogs after racing was as low as 4 per cent but it in reality it was probably lower.

She wants an independent and public inquiry into SA greyhound racing.

"What actually happens to the dogs if they don't make the grade?" she said.

"That's not actually a public matter and we are to contact the SA Greyhound racing industry but then they are self-regulating so they kind of close ranks.

"We want this information made public."

Greyhound Racing SA said it had offered the RSPCA an opportunity to look at its data on a confidential basis, but it was declined.

It said it had put significant resources into greyhound welfare and re-homing, which was increased further after revelations about live-baiting in NSW.

SA Sport Minister Leon Bignell said there was no evidence that practices resulting in a ban interstate had happened in South Australia.

Opponents today rallied at Elder Park in Adelaide's CBD as part of national rallies held across the country.