Gai Waterhouse and Adrian Bott have been granted an adjournment to seek legal advice after being charged by Racing NSW stewards for substituting three horses for a televised track gallop.

Waterhouse described the charge as "incredibly severe, unnecessary and certainly unfair".

"I can't believe you just didn't give us a warning," Waterhouse told a Racing NSW stewards' inquiry on Tuesday.

The training partnership is charged with breaching the rule regarding conduct prejudicial to the image and or/interests of racing with the pair acknowledging galloping Stampede, Fabrizio and Sort After in place of Serena Bay, Debonairly and English at last week's Breakfast with the Stars promotion at Randwick.

Stewards laid the charge after a 30-minute hearing during which Waterhouse and Bott apologised profusely for replacing the horses and insisted they had no intention of bringing racing into disrepute.

Waterhouse said Serena Bay had a muscle enzyme problem, Debonairly had a sore foot and English a sore eye so were not fit to work after an inspection at 3.20am last Tuesday and were replaced before the gallops began about three hours later.

Waterhouse admitted track officials were not notified and not changing the racing colours and saddlecloths was another oversight.

"We apologise profusely. We just didn't think," she said.

"We weren't trying to deceive anyone but we realise it was unacceptable and it won't happen again.

"We didn't want to let people down. The show was on the road. We don't have a lot of time to mull over these things.

"We thought it was better to have four horses there than scratch them. We hoped it would help racing, not hinder racing."

Waterhouse took exception to the use of the phrase 'substituting' horses.

"We have not substituted anything," she said.

"There was no race. Substituting is a very serious offence, this is not a serious offence."

Racing NSW chief steward Marc Van Gestel said Waterhouse, Bott and other trainers were told that only horses entered in Group races scheduled last Saturday were eligible to gallop.

He maintained transparency and integrity were vital and those qualities were compromised by the decision to use alternative horses in an event that was televised live.

Van Gestel said the event was also covered by print and digital media who were under the impression English, Serena Bay and Debonairly were galloping, and detailed their performances accordingly.

He said it would be difficult for the public to understand the rationale behind Waterhouse and Bott's decision.