Four high-class Japanese horses have been confirmed as contenders for The Championships in Sydney.

Real Impact, To The World, Tosen Stardom and World Ace are the first international horses targeting races at Randwick in April.

To The World finished second to champion mare Gentildonna in her farewell race, the Arima Kinen, last Sunday.

He and Tosen Stardom will be aimed at the $4 million Group One Queen Elizabeth Stakes (2000m) on Saturday, April 11 while World Ace and Real Impact will tackle the $3 million Doncaster Mile (1600m) a week earlier.

"These four horses are serious competitors on the world stage," Racing NSW Chairman John Messara said.

"We are very pleased that the connections of the quartet have made the decision to come to Sydney for The Championships.

"We have no doubt they will be very competitive and should bring with them immense interest from the Japanese media."

Messara said Tosen Stardom still had to qualify for the Queen Elizabeth but connections were keen to target a lead-up race like the BMW to raise his rating.

Champion Hong King miler Able Friend is also a possibility for the Doncaster Mile.

Japanese mare Hana's Goal came to Sydney last year and won the Group One All Aged Stakes (1400m) while the other 2014 international visitor Gordon Lord Byron won the Group One George Ryder Stakes (1500m).

Work is underway to convert Canterbury Racecourse into a quarantine centre for the international horses while they are in Sydney.