Limiting this year's Turnbull Stakes to elite horses would do little to boost the number of starters and any critic needs a reality check, Mornington trainer Amy Johnston says.

Johnston has defended her decision to run Skyfire against Winx at Flemington on Saturday, despite backlash over the low-rated gelding being in the Group One race against the unstoppable champion of the racetrack.

Social media erupted with comments on Wednesday claiming the move was making a joke of the high-class Turnbull Stakes and urging the rules be changed so only horses of a certain standard could compete.

"I respect the comments that everyone's saying, and I can see how that would make sense," Johnston told RSN927 on Thursday

"But at the end of the day, we had this Group One race open to - as the rule stands now - any horse, any trainer, that met their criteria with Racing Victoria had their chance to go in it."

There were just seven nominations for the $500,000 race.

Running sixth or last in the Turnbull on Saturday would still give six-year-old Skyfire's owners $10,000, with Johnson already pledging to donate her $1000 trainer's share to the Make-A-Wish Foundation for sick kids.

"There are people out there with little babies and children that are dying and you're carrying on about a horse that was eligible to run in a race who's going for a kick around for some money," Johnston said.

"I think it's a nice little reality check for everyone. There are bigger fish to fry."

Johnston said limiting the race to horses with ratings over 80 wouldn't have opened the nomination floodgates and having a slim field, like 2016's three-horse Caulfield Stakes dominated by Winx, leaves punters up in arms.

"Every horse and every trainer in Australia had the opportunity to race against the wonderful mare and everyone's scared of her," she said.

"If there were only two horses in it, people would be going 'Oh, this is rubbish'. You can't please everyone."

While Skyfire winning with jockey Dwayne Dunn is nearly impossible against Winx, she's a chance to do better than Magicool, the other $301 shot.

The gelding has had two starts with new trainer Tony Romeo after almost a year off, and came last both times.

"At least my horse has been competitive and running well," Johnston said.

"If there's a couple of scratchings, it could end up being that he could run a place in a Group One."