The interim head of Greyhound Racing New South Wales has described how some trainers confronted him and warned that greyhounds would have to be euthanased if live baiting was disallowed.

An Special Commission of Inquiry has heard allegations of serious animal abuse in the greyhound racing industry, including the use of live bait, to "blood" dogs, and the mass slaughter of greyhounds deemed too slow to race.

The inquiry follows an investigation into live baiting by the ABC's Four Corners program, which was broadcast in February.

Paul Newson was appointed CEO in February to replace Brent Hogan, who was stood down after the program aired.

Mr Newson told the inquiry he was "fairly aggressively" confronted by a small minority, who supported live baiting, at a number of industry forums across NSW earlier this year.

He said they warned him that "if (live baiting) wasn't allowed, x amount of greyhounds would be euthanased."

"They would harangue me whilst I was speaking, asking... as to why we had not injuncted Four Corners," he said.

He said that among some participants "there was a rejection of any accountability" and instead they called the ABC journalists "the criminals".

"It was significant enough that they were extremely vocal and they seemed to dominate discussion," he said.

Yesterday, the chairman of Greyhound Racing NSW Professor Percy Allan told the inquiry that live baiting was condemned and prohibited by the sport, and the rules were clear.

Too many dog races: Paul Newson

At today's hearing, Paul Newson delivered a scathing criticism of the previous leadership team, which all but dissolved in the wake of the live baiting scandal.

A live possum is used as bait as a part of a greyhound's race training regime. ( Supplied: Animals Australia )

After stepping into the role of CEO, he said it became clear to him that the regulatory role of the body had "no meaningful welfare strategies" and was, in effect, "non-existent".

He accused the regulator of using "immature practices".

Mr Newson also told the hearing he believed the issue of live baiting could be effectively resolved, but he warned that the industry must deal with the over-production and euthanasing of greyhounds.

He said there existed "a saturation of dog racing" in New South Wales, with too many races and too many clubs.

No measures to control breeding

Earlier, the former chair of the board, Eve McGregor, told the inquiry she was aware thousands of greyhounds were being euthanased every year.

Ms McGregor resigned in February after about three years in the role.

She said that during her appointment there were no measures in place to control breeding.

"We were in the process of introducing a number of different initiatives," she said, such as registering female dogs.

Rules have since been introduced, in July this year.

Ms McGregor also told the inquiry that she became aware of live baiting during the course of her appointment, but said it was "never identified as a major or systemic issue".