New Zealand jockey Opie Bosson will not be disappointed if the predicted rain falls ahead of Melody Belle's bid for the All-Star Mile at Caulfield.

Rain is forecast on Friday, the day before the second running of the $5 million race and Melody Belle has previously shown she can handle affected ground.

A 10-time Group One winner, Melody Belle has been successful at the highest level on both soft and heavy tracks in New Zealand, with her solitary Australian Group One victory in the Empire Rose Stakes at Flemington last spring on soft ground.

Melody Belle is just as effective on firmer surfaces with four of her 15 wins on good tracks.

Bosson made a hit-and-run Melbourne visit to gallop Melody Belle at Caulfield on Tuesday and was brimming with confidence after the work-out.

He said he felt improvement in the mare from her first-up third behind Streets Of Avalon in the Futurity Stakes at Caulfield on February 22.

Bosson thought Melody Belle's effort was good given the way the track raced that day and noted the mare had stepped up her fitness.

"I just can't get over the improvement in her from when I rode her last time until the gallop today," Bosson said.

"She worked outstanding for her. She changed legs at the right time and felt really good.

"When she's going well, she travels you through the line.

"The gallop before the Futurity the other horse had her off the bit a little bit, but today I had to take another hold before the line.

"Coming in after that gallop today, and with a bit of rain about, I'm very confident.

"It would be nice to win it and I think I've got the horse to do it."

Paul Richards, father of trainer Jamie Richards, is looking after the mare in Melbourne and said barrier five was perfect for Melody Belle who is second favourite behind Alligator Blood.

"It gives Opie options," he said.

"If they go hard she can just get back a wee bit. If they don't go hard she can go forward a bit."