Horses trained by Irish maestro Aidan O'Brien dominate the positions at the top of weights for the Caulfield and Melbourne Cups.

Handicaps for the Cups were announced by Racing Victoria's Greg Carpenter on Tuesday.

Last year's English Derby winner Anthony Van Dyck has been given top weight of 58.5kg in the Melbourne Cup.

In the Caulfield Cup he's joined by his O'Brien-trained stablemate Japan as equal top weight, again with 58.5kg.

Japan and another O'Brien galloper, champion mare Magical, weren't entered for the Melbourne Cup.

Magical is the third highest-weighted horse in the Caulfield Cup with 58kg.

Anthony Van Dyck has the distinction of being the first English Derby winner to be given top weight in a Melbourne Cup.

RV's international recruitment manager Paul Bloodworth said Anthony Van Dyck was still in the mix to come to Australia with O'Brien planning to send five horses to Melbourne.

Bloodworth said the trainer would have several runners this weekend in Ireland and England before choosing which of them will make the trip.

Carpenter said O'Brien's Cups entries were stand-out performers over the past 18 months and were handicapped accordingly.

"The joint Caulfield Cup top weights, Anthony Van Dyck and Japan, were both Group One winners over 2400 metres in 2019 and have been placed behind the world's highest-rated horse Ghaiyyath this year," Carpenter said.

"The outstanding Magical, who is a six-time Group One winner and nominated for the Caulfield Cup only, has 58kg and will need to set a weight-carrying record for a mare with Tranquil Star claiming that mark when winning the 1942 Caulfield Cup with 56kg."

O'Brien's globetrotting mare Magic Wand is also nominated for the Caulfield Cup and has 55kg.

His 2019 Irish Derby winner Sovereign is among a trio of horses allotted 57kg in both races, making them the equal second-highest weighted horses in the Melbourne Cup.

The other two are defending champion Vow And Declare, trained by Danny O'Brien, and Godolphin's three-time Group One winner Avilius.

Vow And Declare has gone up five kilograms from last year but Carpenter explained there was a 1.5kg increase due to the weight-for-age scale.

His stablemate Russian Camelot has been allotted 53.5kg, making him the highest-weighted northern hemisphere-bred three-year-old in both races, alongside Aidan O'Brien's 2020 Irish Derby winner Santiago.

Carpenter said the South Australian Derby, which Russian Camelot won, was the highest-rated Derby run in Australia last season.

Paul Preusker's Surprise Baby has been handed 54.5kg in both races, a kilogram more than what he carried in the Mebourne Cup last year when he finished an unlucky fifth.

Carpenter said he had set a challenge for Chris Waller's star mare Verry Elleegant in the Cups giving her 55kg in each race.

"Makybe Diva is the only mare to carry more than 55kg to victory in the Melbourne Cup having done so in 2004 (55.5kg) and 2005 (58kg), the latter being the last time a mare has placed in our most famous race."