Admire Rakti will have to carry topweight in his bid to join Delta Blues as a Japanese winner of the Melbourne Cup.

Last year's Japan Cup fourth placegetter, Admire Rakti was given 58kg for Australia's greatest horse race on November 4 when weights were released on Tuesday.

This year marks the first since 2010 that the spring carnival will feature Japanese participation and only the second time since Delta Blues and Pop Rock notched a quinella for Japan in the 2006 Melbourne Cup.

Racing Victoria's chief handicapper Greg Carpenter said delivering his 10th set of Melbourne Cup weights was one of his most challenging because there was not a natural topweight.

"I am obligated to release a topweight of 58 kilograms, however with recent staying champions Fiorente, Dunaden and Americain now retired there was no natural topweight so I've had to effectively lifted weights two kilos for the majority of runners," Carpenter said.

He said that was the reason for the vastly different set of weights for the Melbourne Cup to this year's Caulfield Cup where Eclipse Stakes winner Mukhadram was the original 58kg topweight.

The last original topweight to win the Melbourne Cup was Comic Court in 1950.

Godolphin stayer Cavalryman, last year's Caulfield Cup winner Fawkner, 2012 Cup winner Green Moon and dual Melbourne Cup runner-up Red Cadeaux have 57kg.

Bande, the second Japanese runner set to contest this year's race, has 56.5kg.

Dandino and last-start Prix Kergorlay winner Protectionist also have 56.5kg.

The Japanese runners are in quarantine at Tokyo Racecourse and will arrive in Melbourne on Saturday.

This year's favourite The Offer also has 56.5kg while star mare Silent Achiever has the same weight.

Only Makybe Diva has carried more weight to victory as a mare when she had 58kg winning her third Cup in 2005.

Makybe Diva's three-quarter sister La Amistad has 51.5kg.

As nine-year-olds, popular international Red Cadeaux and Cavalryman would have to create history at Flemington.

"If Red Cadeaux or Cavalryman win the race they will be the oldest Melbourne Cup winner in history," Carpenter said.

The Offer has been well-supported as the $9 favourite while Silent Achiever is the worst result on TAB's early Cup book.

At $15, Silent Achiever is on the second line of betting with the Japanese duo.