The Melbourne spring carnival is in countdown mode with entries for two of the biggest races scheduled for release.

Nominations close on Tuesday for the Caulfield Cup (2400m) on October 17 and the Cox Plate (2040m) at Moonee Valley on October 24 and will be known in the afternoon.

A lot of talk will centre on the likely make-up of the fields before weights are released on September 2.

Melbourne Cup nominations close on September 1, with weights for the famous race at Flemington on November 3, released two weeks later.

The big three races were all won by internationally trained horses last year with Ireland's Adelaide winning the Cox Plate, Japan's Admire Rakti taking the Caulfield Cup and German horse Protectionist the Melbourne Cup.