Racing Australia, Racing NSW, Racing Victoria and Harness Racing Australia were all questioned after the ABC's 7.30 program exposed mistreatment of horses.

It was the final hearing on the Rural and Regional Affairs and Transport inquiry into the feasibility of a national horse traceability register, which is expected to hand down its report this month.

Greens senator Mehreen Faruqi asked the racing bodies to commit to banning their horses from being sent to knackeries and also giving them digital 'do no slaughter' tags.

Ms Faruqi also asked they commit to the rehoming every horse in the industry once they had finished racing.

The bodies all supported the register but stopped short of making any commitments to Senator Faruqi, saying some were simply not possible.

"We want them to be healthy but the reality is we're not going to get to 100 per cent (rehoming)," Racing Australia chairman Gregory Nichols said.

"Let's assume a racehorse gets to eight or nine, the reality is it's then sold on, we know where it goes but there could be numerous sales that occur after leaving the racing industry.

"I don't think Racing Australia can be responsible entities and give you a guarantee those horses have an appropriate life until they pass away.

"There will always be slippage, our task is to mitigate that slippage as much as we can."

Harness Racing Australia chief executive Andrew Kelly said his position that rehoming every horse wasn't practical had not changed in the wake of the ABC report.

"Regardless of what we saw, and we've made our positions very clear of what we saw on that program, there has been no shift in our position," Mr Kelly said.

"We're not in a position to head down that path with giving a commitment because I don't think we could put our hand on our heart ever and be able to give that promise.

"The job for us and our clear responsibility is to provide as many opportunities for horses retired from activities in our racing industry to live full and quality lives."

Australian Associated Press