New South Wales is set to be the first Australian state to ban greyhound racing, after an inquiry found "overwhelming evidence of systemic animal cruelty, including mass greyhound killings and live baiting".

But the industry is fighting the ban, claiming evidence has been overblown and innocent greyhound owners and trainers will lose their livelihoods as a result of the criminal activity of a minority.

How did this come about?

The NSW Government set up a special commission of inquiry into the NSW greyhound racing industry in response to a Four Corners program shown on ABC TV in 2015.

It showed racing greyhounds being enticed to chase, maul and kill live animals such as rabbits, in an effort to make them more enthusiastic racers.

Sorry, this video has expired GRAPHIC FOOTAGE: Four Corners exposed the practice of 'live baiting' greyhounds.

This practice, known as 'live baiting' or 'blooding', is a criminal offence in NSW.

But the broad and far-reaching terms of reference charged the commission with investigating animal welfare issues in the industry and whether those issues could be dealt with to allow greyhound racing to continue.

As well as live baiting, the commission found evidence that at least 50 per cent of dogs bred were deliberately killed because they were not competitive racing greyhounds.

In addition, it estimated that around 20 per cent of greyhounds who compete in races are injured, though Greyhounds NSW disputed this estimate.

How widespread is live baiting?

The commission heard evidence from several witnesses who had used live baiting to train greyhounds themselves and had seen others do it.

Several of them estimated that up to 90 per cent of trainers used live rabbits to train greyhounds and one said he could not think of any trainers who did not use live baiting.

The commission concluded that the evidence from these witnesses about the proportions of trainers using live baiting was "debatable" and "based on gossip".

One trainer with 40 years' experience, who had practised live baiting himself and helped others to do it, said about 10 per cent to 20 per cent of trainers used live baiting.

His evidence was regarded by the commission as more likely to be correct based on his involvement and knowledge of live baiting.

The commission found that the practice of live baiting was "rampant and chronic" and "firmly enmeshed" in the greyhound racing industry and that the Greyhounds NSW board knew since at least 2009 that live baiting was an issue and had done nothing about it.

It concluded that "probably about 10 to 20 per cent of trainers" practised live baiting at the time the Four Corners program was screened.

How many greyhounds are killed in NSW each year?

When a litter of greyhound pups is born, Greyhound Racing NSW must be notified.

Pups are then registered to race at the age of 12 months, trained between 12 and 15 months and are ready to race at around 16 months of age.

They generally race until the age of four and a half and they live to between 12 and 15 years of age.

Around 98,000 greyhounds were bred in the past 12 years in NSW but only 6,800 greyhounds are registered.

Some of the remaining dogs will be unregistered pups, some exported to other countries, some kept as pets and some would have died of natural or accidental causes.

At best, the commission estimated that 22 per cent of the 6,295 pups born in 2015 could be found homes by welfare organisations or the industry's own 'Greyhounds as Pets' program.

The evidence reported to the commission showed that at least 40 per cent of the greyhounds bred never made it to the track.

As a consequence, the commission estimated that somewhere between 49,000 and 68,000 dogs (50 to 70 per cent) born in the past 12 years have been killed because they never were, or no longer were, capable of being competitive greyhounds.

The industry calls this culling of dogs "wastage".

The commission said the precise number of greyhounds destroyed by the industry each year was not known.

A separate report by senior barrister Clive Steirn found it was likely at least 99 greyhounds were brutally killed and buried at one single Hunter Valley property over four years, between 2009 and 2013.

Why did the commission suggest the industry could not reform?

The commission made 80 recommendations to the NSW Parliament.

Seventy-nine of these recommendations focused on ways to prevent live baiting and improve industry governance to protect animal welfare.

But the first recommendation asked the Parliament to consider whether greyhound racing should be banned.

Over-breeding and the consequent "wastage" of dogs was central to the commission's view that the industry had failed community expectations that it was ethical and humane.

"The industry has failed to address the issue of wastage successfully and appears unlikely to do so in the foreseeable future," it noted.

It said the economics of the industry meant it would not be able to reduce the large-scale killing of dogs to a level tolerable to the community.

The industry's own figures showed that 7,596 pups were needed each year to meet the almost 100,000 "starts" for dogs in more than 1,200 scheduled races.

Cutting the number of race meetings to 593 - the minimum Greyhounds NSW must run under an agreement with the TAB regarding the distribution of gambling revenue - would need 4,695 pups to be bred, according to the commission's calculations.

"That means that to support the continuation of the industry at least 2,000 healthy greyhounds will be destroyed each year," it said.

Even under two scenarios put forward by Greyhounds NSW to maintain race numbers but cut the "wastage", around 3,000 to 4,000 greyhounds would still need to be destroyed each year.

What did the Government say about proceeding with the ban?

NSW Premier Mike Baird said shutting down the industry was a difficult but necessary decision.

"This is the inevitable conclusion to be drawn from the appalling revelations in Mr McHugh's report and his considered view that any other measures are unlikely to protect animals from further cruelty," he said.

Mr Baird described the evidence of animal cruelty heard by the commission as "chilling and horrific".

"He has shone the light on an industry that has overseen the slaughter of tens of thousands of healthy dogs whose only crime was they weren't fast enough," he said.

"He's also shown an industry which has turned a blind eye to the barbaric practice of live baiting. He's shown that the industry has a culture of deception.

"Indeed the commissioner has found that it is no longer entitled to the trust of the community."

How many people will be affected by the ban?

Estimates vary as to how many people are involved in greyhound racing in NSW and will be affected by the ban.

A NSW Government-commissioned report found that greyhound racing contributed more than 2,700 full-time jobs to the NSW economy.

By way of comparison, there were more than 21,000 full-time jobs in thoroughbred horse racing and more than 3,500 in harness racing.

A report commissioned by Greyhounds NSW estimated there were 1,561 full-time jobs in greyhound racing, with about two-thirds of these jobs directly related to the industry.

The two reports show that between 36 per cent and 64 per cent of the full-time jobs in greyhound racing are in regional areas outside Sydney.

But many more people participate in the industry who are not classified as having full or part-time jobs, working as trainers, breeders, owners and volunteers.

The NSW report puts the number of people participating in greyhound racing at more than 15,000, of which more than 13,000 are involved in producing racing dogs.

Nearly three-quarters of these participants are in regional areas.

In comparison, more than 53,000 people participated in thoroughbred racing, and more than 13,000 in harness racing.

Finally, there were 282,000 attendances at NSW greyhound race meetings in 2012-13.

Where else is greyhound racing banned?

According to the commission's report, commercial greyhound racing — where it is legal to bet on races and the industry is formally regulated — operates in eight countries: Australia, Mexico, Macau, New Zealand, Republic of Ireland, United Kingdom, five states of the USA and Vietnam.

There is non-commercial greyhound racing in 21 other countries, including many European countries, according to Grey2K USA, a greyhound protection organisation.

They report that commercial greyhound racing has been banned in 40 US states and the commission reported that it was banned in South Africa in 1949.