The richest race of the Sydney autumn carnival will offer $4 million stakes - and the chance to score an invitation to the biggest show in United States racing.

In an international boost for the Queen Elizabeth Stakes' profile, the winner of the weight-for-age will have its nomination and travel costs covered for the Breeders' Cup Turf Classic (2400m).

The $40,000 subsidy, paid by Breeders' Cup organisers, will also be available to the winners of the Doncaster Mile and the TJ Smith Stakes.

The Australian Turf Club said it instigated the move on the basis a colt or entire wins the Queen Elizabeth.

A horse such as New Zealand star It's A Dundeel, already a valuable stallion proposition, can enhance his appeal to northern hemisphere breeders if he makes an impact on the United States racing stage in the Breeders' Cup series.

The four-year-old, entered for a Randwick barrier trial on Monday, is the early favourite to win the Queen Elizabeth.

Melbourne Cup winner Fiorente is another horse with the right profile to make an overseas bid.

"Fiorente and It's A Dundeel have pedigree appeal to northern hemisphere breeders so if they were to race on after this season and win a Breeders' Cup Turf it would bolster their international stud appeal," the ATC's Matt Rudolph said.

This year's Breeders' Cup series will be held at Santa Anita Park, California, on October 31 and November 1.

Run over 2000m, the Queen Elizabeth Stakes will be held on the second day of The Championships at Randwick on April 19.

The Doncaster Mile and the TJ Smith Stakes will be highlight races on the opening day, April 12.