Maloney fell awkwardly during training which means the Rio 2016 49erFX runners-up will have to sit out at Australia's Royal Geelong Yacht Club.

The event is the last major class title before the Tokyo 2020 Olympics and begins tomorrow.

As well as world titles, the event also has importance as it will be used by several countries to select their crews for the Games in Japan.

With each nation only allowed one boat in each fleet, it leads to rivalries between sailors from the same country.

New Zealand had already earned a Tokyo 2020 quota spot in the 49erFX thanks to Maloney and Meech, but has not yet picked its Olympic sailing team.

"The girls are devastated, obviously, being so close to the World Championships and having this sort of injury," said New Zealand coach Nathan Handley. 

"They were in really good shape. 

"Everything was going well.

"They were sailing well, the boat was going well and we definitely thought we had a good shot at the podium here in Geelong."

The 2019 World Championship in Auckland only took place between December 3 and 8 last year.

Dutch pair Annemiek Bekkering and Annette Duetz have returned to defend their 49erFX world title, which they are hoping to win for the third time in a row. 

Brazil's Olympic champions Martine Grael and Kahena Kunze are also in the fleet, after winning silver in Auckland.

Ida Nielsen and Marie Olsen of Denmark, the 2019 bronze medallists, are another crew to return.

In the 49er, New Zealand's reigning Olympic champions Peter Burling and Blair Tuke will bid for a sixth world title after triumphing in Auckland on home water.

Germany's silver medallists from last time, Erik Heil and Thomas Ploessel, will look to go one better, with Britain's 2019 bronze medallists Dylan Fletcher-Scott and Stuart Bithell also lining up.

Spaniards Diego Botin and Iago Lopez Marra won the warm-up Oceania Championship event so should also be a threat.

The Nacra 17 will feature Italy's reigning champions Vittorio Bissaro and Maelle Frascari.

Argentina's Olympic gold medallists Santiago Lange and Cecilia Carranza will be among their challengers, as will Denmark's 2019 silver medallists Lin Cenholt and CP Lubeck.

Hosts Australia will look to Jason Waterhouse and Lisa Darmanin, the bronze medallists last time, to mount a challenge.

Racing in Geelong will run through until Saturday (February 15).