Just two cents of every dollar bet so far with the TAB on the Cox Plate has gone on a horse not called Winx.

The champion opened at $4 minutes after her second consecutive Cox Plate victory in 2016 and was already at $1.60 in April

By this week when nominations were received, she had been crunched even further to $1.40.

Punters pessimistic about the world's best turf horse's chances of winning a record-equalling third Plate can get at least $26 on any other horse.

The TAB is holding two bets of $20,000 at $1.50 while another bet laid when Winx was at $2.80 could turn $18,000 into $50,000.

All money has been laid under "all in" conditions, meaning punters will forfeit their money if the champion misses the race.

"Despite the cramped odds, we have already seen a host of big bets for her and not surprisingly, she has been well backed through multi bets," TAB spokesman Nick Quinn said.

Hartnell, who was eight lengths behind Winx when second in last year's race, sits on the second line of betting at $26 with Australian Cup winner Humidor and reigning Breeders' Cup champion Highland Reel who ran third to the mare in 2015.

Unbeaten three-year-old Royal Symphony, British raider Scottish and Australian Bloodstock-owned Tosen Stardom are at $34.

Only 11 other horses, including Lindsay Park filly Catchy, are listed in double figures.

It's a similar story with the major corporate bookmakers who all have Winx around the $1.50 mark and her opposition the other side of $20.