Akzar improving on last year's Warrnambool Cup result could be one of the few sure things of the three-day May carnival.

Akzar finished 18 lengths from Banca Mo when 13th in 2013 but the gelding has undergone an amazing transformation since joining the Darren Weir stable.

Weir became the seven-year-old's third trainer since arriving in Australia and only the exciting import Our Voodoo Prince has beaten Akzar in 2014 with the Chris Waller-trained galloper having the better of him at Flemington and Caulfield.

But Our Voodoo Prince is not in the Warrnambool Cup, which heightens jockey Brad Rawiller's confidence in Akzar's chances.

However, Rawiller said the track was one of the biggest obstacles facing Akzar in Thursday's $200,000 race.

The Warrnambool Cup will be the 27th race held on the track in three days and heavy rain on Tuesday ensured the course would remain affected on Thursday.

Rawiller said the traffic on the racetrack during the first two days of the carnival was likely to create a fast lane that he must find to give Akzar the best possible chance.

"I'll be working on finding the fast lane during the day," Rawiller said.

"But a few other jockeys might find it as well so there will be a few riders thinking the same thing as me.

"Finding the fast lane is one thing but getting into a good position to take advantage of it is another thing."

Akzar is the easing $3.80 favourite in Warrnambool Cup betting but his stablemate Shiny Buttons firmed from $12 into $5.50 after an impressive win on Tuesday.

Banca Mo is a $9 chance to score back-to-back Cup wins while the Robert Smerdon-trained Westsouthwest is a $7 hope.

Smerdon considered running Westsouthwest in a hurdle race during the carnival but the stayer's owners wanted to start the Group One placegetter in the Cup.

Smerdon said Westsouthwest had progressed well from his last-start win at Caulfield to have a strong chance of taking out the race he won with Tinamou in 2010.