Surprise Baby has been penalised 1kg for both the Caulfield and Melbourne Cups for his win in The Bart Cummings at Flemington.

Melbourne Cup favourite Surprise Baby has been penalised 1kg for his win in The Bart Cummings at Flemington.

The Paul Preusker-trained Surprise Baby guaranteed himself a spot in the Melbourne Cup (3200m) on November 5 with his win in Saturday's Bart Cummings and in the process the lightly raced stayer was elevated to equal favouritism with Turnbull Stakes runner-up Finche.

Racing Victoria's Greg Carpenter announced the penalty on Monday, which takes Surprise Baby's Melbourne Cup weight from 52.5kg to 53.5kg, opening the door for Jordan Childs to retain the ride.

He was also given 1kg for the Caulfield Cup, going from 53kg to 54kg and moving from 41st to 29th in the order of entry.

"In determining the penalty, consideration was given to the dominant nature of Surprise Baby's victory and his emerging staying talent, balanced against the fact that his win was over Supernova and Wolfe, who are both on the minimum weight in the Cups," Carpenter said.

"Almandin was penalised 1kg for his Bart Cummings victory before winning the Melbourne Cup with 52kg at his next start in 2016."

Surprise Baby has won five of his 10 starts including the Group Two Adelaide Cup over the Melbourne Cup distance of 3200m in March at his sixth start with lightweight jockey Dean Holland aboard.

Childs, who usually rides at 55kg and above, told RSN 927 he would talk to Preusker about the possible ride.

"It's the favourite in the Melbourne Cup so I think I'll have a crack," he said.

Surprise Baby firmed from $18 to $9 for the Melbourne Cup after his 1-1/2-length victory on Saturday.

Cross Counter and Marmelo, who ran one-two last year, are at $15.