The Peter and Dawn Williams-trained mares will start warm favourites in their respective races.
Media Sensation contests the Auckland Thoroughbred Breeders Stakes (1400m) after winning impressively in her first start as a 4yr-old at Te Rapa over 1200m earlier this month.
"It was a very nice run last start. She has come through the race very well," Peter Williams said.
"She has developed quite a bit since her 3yr-old season. She is quite strong now.
"I am very happy with her and she has got a nice draw in barrier 2."
TAB bookmakers opened Media Sensation the $2.80 favourite for the Breeders' Stakes ahead of Princess Kereru ($3.60) and Queen of Diamonds ($5.50).
A group-1 clash is in prospect for the pair.
"Provided they come through their races all right, both mares will press on to the Railway [1200m, at Ellerslie on New Year's Day]," Williams said.
Marzemino is set to start favourite in tomorrow's Counties Bowl (1100m).
Bookmakers opened the mare at $2 win odds ahead of second-favourite Julius ($7).
Marzemino is seeking her fourth consecutive win in what will be her biggest career test.
"We are happy with her. She is in great form," the trainer said.
"She has got a good draw (barrier 5) and if she is right on the day she will be right in it.
"It is the toughest field she has had to take on ... but I think she is up to them. She has done everything right and everything being equal, she will be a big chance."
Like her stablemate, Marzemino won her first start of the season impressively over 1200m.
- Additional reporting NZ Racing Desk
