World Rugby has criticised the performances of referees in the opening games of the Rugby World Cup.

Rugby union's governing body issued a statement after match officials came under fire during the first round of pool fixtures in Japan.

The most notable incident occurred on Saturday and involved Australia wing Reece Hodge, whose tackle on Peceli Yato left the Fijian concussed and later led to a citing, despite the on-field referee and TMO deeming it legal at the time.

In the tournament's opening game, Japan lock James Moore's no-arm tackle on Russia's Vasily Dorofeev also went unpunished.

A statement from World Rugby said: "Following the usual review of matches, the match officials team recognise that performances over the opening weekend of Rugby World Cup 2019 were not consistently of the standards set by World Rugby and themselves, but World Rugby is confident of the highest standards of officiating moving forward.

"Elite match officials are required to make decisions in complex, high-pressure situations and there have been initial challenges with the use of technology and team communication, which have impacted decision-making. These are already being addressed by the team of 23 match officials to enhance consistency. 

"Given this proactive approach, a strong team ethic and a superb support structure, World Rugby has every confidence in the team to ensure that Rugby World Cup 2019 delivers the highest levels of accurate, clear and consistent decision-making."