Melbourne Cup winner Cross Counter must overcome a tough penalty if he is to retain his crown at Flemington on November 5 after the weights were released on Tuesday.
The Charlie Appleby-trained four-year-old bids to become the first horse since Makybe Diva in 2005 to win back-to-back editions, but must carry 9st – a stone more than last year. Only 1973 winner Gala Supreme has faced a larger rise for his follow-up bid.
Last year's runner-up, Marmelo, and the third, Prince Of Arran, will remain on the same weights of 8st 9lb and 8st 5lb.
The Aidan O'Brien-trained Kew Gardens, who won the 2018 St Leger, has been given top weight of 9st 1lb, and the trainer could also be represented by Il Paradiso, who has been allotted 8st 3lb.
Racing Victoria's chief handicapper Greg Carpenter said: "Kew Gardens was the world's joint-highest-rated stayer alongside Stradivarius last year, so is a worthy topweight among the 152 entries.
"Given the nature of Cross Counter 's victory last year and the natural progression in the weight-for-age benchmark from a three-year-old, I felt it was an appropriate penalty to impose.
"Inevitably the internationals will again pose a formidable challenge to the locally-trained stayers, with the first three home in the 2018 Melbourne Cup all set to return to Melbourne this year.
"However, if the likes of Steel Prince and Adelaide Cup winner Surprise Baby can maintain their form throughout the spring, I'm sure the visiting horses will have a real fight on their hands."
The weights were also issued for the Group 1 Caulfield Cup on October 19, with the entries including Prince Of Arran (8st 4lb) and the David Menuisier-trained Danceteria (8st 8lb).
First acceptances for the Melbourne Cup will be taken at noon on Tuesday, October 1.