Doctor Ross Padrana is the lead plaintiff on legal papers served to Racing NSW on Wednesday alleging licensing by racing's regulator would be a restraint of trade.

Vets believe the rule is not necessary as they are already licensed under the NSW Veterinary Practitioners Act.

Racing NSW remains determined to license vets under the rules of racing, but chief executive Peter V'landys would not comment on the court action on Thursday.

The Veterinary Practitioners Board, Equine Veterinarians Australia and Racing NSW have struggled to find common ground on the licensing issues with implementation of the rule deferred until January 15.

The implementation was originally planned for December 1 but was put back after vets voted unanimously that they would not be licensed at an information session held by Racing NSW.

Discussions have since reached a stalemate leading to legal action by Dr Padrana. It is believed that parties have not talked for several weeks.

Vets, under their code of conduct are supposed to conform to the rules of racing, but Racing NSW is keen to have rules that bring them under its jurisdiction.

“We don't want to have happen to our sport what happened in the AFL and NRL where unlicensed people come in and affect the integrity,” V'landys said.

“We are being proactive, not reactive with this rule and we stand firm on our resolve to have the highest of integrity for punters and our participants.”

The Australian Veterinary Association labelled Racing NSW's proposal to licensing "an insult" when it was first mooted, while EVA will fight the rule. The vets' main concern is the power given to Racing NSW to revoke a licence at will, without reason.

"We are held to the highest integrity," EVA president Frank Condon told Fairfax Media last month.ef

"Our members should be concerned at the intrusion of Racing NSW into the jurisdiction of the [Veterinary Practitioners Board]. As part of the act we are already compelled to follow the rules of racing.

"There are processes that would be followed if a vet didn't follow the rules but we think the best way to handle it is as required under the act by an independent board of peers [rather than Racing NSW]. We are happy with the course of action to come from the meeting but we still have our differences."