The world champion triumphed in the most recent leg at home in Bermuda and also claimed a dominant victory at last month's Commonwealth Games in Gold Coast.

Duffy will face a different challenge on a Yokohama course which will be less hilly and hot than in Bermuda, but could be technical and slippy if there is the anticipated rainfall in Japan.

She will face opposition from American series leader Kirsten Kasper and her team-mate Katie Zeferes.

Rachel Klamer of The Netherlands and British duo Jodie Stimpson and Non Stanford will also contend along with a home team led by Ai Ueda, Juka Sato and Juko Takahashi.

The International Triathlon Union-organised event also marks the start of a two-year qualification period for the Tokyo 2020 Olympics.

Spaniard Mario Mola starts as favourite in the corresponding men's race as he seeks to bounce back from fourth place in Bermuda.

Fellow countryman Fernando Alarza will be among his leading rivals along with France's under 23 World Championship silver medallist Dorian Coninx. 

Norway's Kristian Blummenfelt will be seeking to build-upon his bronze in Yokohama last year while South Africa's Commonwealth Games champion Henri Schoeman is another highly-rated starter.

The women's race is due to take place at 10:06am tomorrow.

The men's race should follow at 1:06pm.