The number of potential rivals to Winx in the Cox Plate has been reduced by more than half after first declarations.

The eligible field for the Cox Plate has been reduced to 63 from 135 after Tuesday's first acceptance stage for the $5 million Moonee Valley race on October 27.

Among those still in contention for a shot at stopping Winx win a record fourth Cox Plate are nine international horses, up from five in 2017.

They include Godolphin invitee Benbatl, trained by Saeed bin Suroor, along with the Aidan O'Brien-trained quartet of Cliffs Of Moher, Deauville, Hunting Horn and Rostropovich.

Another Godolphin trainer, Charlie Appleby, has three left, Emotionless, who is set to enter quarantine on Thursday, and Blair House and last year's placegetter Folkswood who both arrived in Melbourne on Saturday.

Caulfield and Melbourne Cups topweight Humidor, who finished second to Winx last year, is one of seven horses champion trainer Darren Weir still has in contention for the Cox Plate.

Notable absentees from first declarations are European invitees Poet's Word and Lancaster Bomber along with Japan's Neorealism.

First declarations also closed on Tuesday for the Caulfield Guineas with 98 remaining in contention, down from 267 nominations, and 107, down from 261, for the Thousand Guineas.