It's business as usual for outgoing Racing NSW chief steward Ray Murrihy who has announced his retirement.

Murrihy had planned a low-key end to his 46-year career, 21 years in the top integrity job in NSW, but spent Monday fielding calls in between conducting an inquiry.

He has been chief steward in NSW for 21 years and admits his retirement has been delayed by the ongoing cobalt inquiries in recent months.

But he has decided the time is right for his deputy Marc Van Gestel to take over.

"I didn't really want an announcement. I probably decided 18 months ago it was coming but then the cobalt inquiries came up," Murrihy said.

"I've had a busy day with an inquiry on another matter and I've also had a lot of phone calls from past stewards who have gone on to other things.

"The time will come when I will reflect on the past 21 years but I'm still going to be busy over the next few weeks."

Murrihy will leave his post on June 3 with Racing NSW chief executive Peter V'landys describing his contribution to racing as immeasurable.

"Ray has been a racing administrator of the highest calibre," he said.

"He is the Black Caviar of stewards and has done an exceptional job, to say the least."

Australian Turf Club chairman Michael Crismale said Sydney racing was the better for Murrihy's input.

"Week in and week out, over several decades, he has unfailingly ensured the integrity and fairness of our great sport," Crismale said.

"He has left a great legacy and example for so many other stewards to follow across Australia and beyond, and retires right at the top of his game with the greatest of respect of all in the industry."