The RSPCA has launched an extraordinary attack on the WA greyhound industry labelling it "highly secretive" over its refusal to release historical euthanasia figures.

Until now, RSPCA WA has stood by the industry and its ability to self-regulate, but it is now calling on the WA Government to set up an independent welfare and integrity body to oversee the industry.

"The industry been very secretive and clandestine in my opinion," RSPCA WA president Lynne Bradshaw said.

"It won't release information and the public is demanding more transparency."

About 600 greyhounds are bred in WA each year. ( ABC News: Robert Koenig-Luck )

"There is move away from that [self-regulation] across the country, it just doesn't work. I don't think Western Australia should be any different."

While the industry spends about $200,000 a year on finding homes for unwanted dogs, there are many animals that are not rehomed.

The industry's adoption program GAP rehomes around 120 dogs a year, but one volunteer-run group alone manages to find homes for another 300.

Around 600 Greyhounds are whelped in WA every year.

Detailed rehoming data unavailable

The RSPCA, Labor and the Greens have been asking the industry to tell them how many dogs have been put down because they deemed unsuitable for rehoming by GAP.

"If there is nothing to hide, why not put the figures out," Ms Bradshaw said.

"They've been breeding thousands of animals over a long period of time. What percentage of greyhounds are rehomed and do they live out their lives to the full? I can assure you that most of them don't," she said.

The RSPCA's Lynne Bradshaw says it is time the greyhound industry opened its doors. ( ABC News: Laura Gartry )

But the industry will only provide the figures for the last three years, which show 57 dogs due to be rehomed were put down.

Manager of Greyhound Racing at Wagering and Racing WA (RWWA) Barry Hamilton said the euthanasia data for the last 10 years would need to be recovered.

"It's currently into a database so that the data is there, but it's not very granular so what we have is data in really bulk amounts," he said.

"I think what we need to understand is, the raw figures as they are, aren't with context."

RWWA has refused to dedicate the resourcing they claim is required to provide the data.

"We will need to understand the value of that, I mean that's a significant body of work," he said.

"I need current data to make strategies, so the historical data doesn't necessarily provide me with the answers; the current data certainly does.

"I don't have control of what happened in the past."

But the RSPCA believes the public deserves to know the whole story.

New kennels expanded for rehoming

Mr Hamilton said greyhounds rehomed by GAP had to pass the national temperament assessment so euthanasia was inevitable for some of the dogs.

But he conceded the rehoming rate could be improved.

"So the figures at the moment, obviously are at a point where the racing and wagering executive and the board, have committed significant resources to improving those figures," he said.

Mr Hamilton said RWWA it had provided $500,000 to expand a new kennel facility in Southern River as part of new rehoming strategy.

The RWWA would not allow the ABC to film or access the facility and declined to answer any further questions about it.

Ms Bradshaw said industry needed to open its doors.

"The public can't expect to have confidence, if the shutters are pulled down," she said.

RWWA said a new national data system called Aus Chase would incorporate GAP data from 2014 onwards.

Racing Minister Brendon Grylls did not respond to the RSPCA's concerns directly, but defended the industry's performance overall.

"The high standards upheld by the WA racing industry can be seen through the recent... investigation that saw no evidence of live baiting in WA, despite a $10,000 reward being offered for information leading to a conviction."