Jameka has been re-handicapped for the Caulfield and Melbourne Cups following her impressive win in the Naturalism Stakes at Caulfield.

Racing Victoria handicapper Greg Carpenter penalised the Ciaron Maher-trained mare a half-kilogram on Monday after her 3-3/4 length win in Saturday's Group Three race over 2000m.

The penalty takes last year's VRC Oaks winner's weight to 52kg in both Cups.

Carpenter said Jameka's win was decisive in defeating Sydney Cup winner Gallante.

"She carried 3kg less than Gallante on Saturday and with the 0.5kg penalty she now has 1.5kg less than Gallante in both the Caulfield and Melbourne Cup," Carpenter said.

"Historically speaking, Leilani (1974) and How Now (1976) are the only four-year-old mares to carry 52kg to victory in the Caulfield Cup.

Jameka leapt to $7 equal favourite for the Caulfield Cup following her Naturalism victory but following the announcement of the penalty Hartnell firmed to $6 outright favouritism.

Carpenter also announced last Friday's Newcastle Cup winner Sacred Master has been re-handicapped to 51kg, a rise of 0.5kg for the Caulfield Cup while escaping a Melbourne Cup penalty.