The surfing test event for Tokyo 2020 began at Tsurigasaki Beach today ©Getty Images

Heavy fog and small waves briefly disrupted the opening day of the surfing test event for Tokyo 2020 as International Surfing Association (ISA) officials insisted the conditions would be "absolutely adequate" for the sport's Olympic debut.

The start of competition was delayed by an hour because of the weather and minimal waves at Tsurigasaki Beach.

Rainfall also greeted the competitors in the water once the fog had lifted before the sun began to shine during the later heats.

Tokyo 2020 and the ISA are expecting waves of between 1-1.5 metres during the test event, although they will be hoping for bigger during the surfing events at the Games.

According to Reuters, Japanese surfers Shino Matsuda and Hiroto Ohhara both admitted the waves were small on the first day of the event.

ISA executive director Robert Fasulo insisted, however, that the worldwide governing body was satisfied with the conditions.

"We depend on mother nature, we depend on the natural conditions as they present themselves," Fasulo said, according to Reuters.

"We are very confident and part of the reason why we are here in this period is to see how the conditions are running during the format.

Some of the surfers admitted the waves on the first day of competition were small ©Getty Images
Some of the surfers admitted the waves on the first day of competition were small ©Getty Images

Fasulo added: "I think that, from what we have seen, and we are on schedule, that the conditions are absolutely adequate.

"This is absolutely contestable conditions if you look and see there are some great waves being ridden."

The surfing competition is part of the "Ready Steady Tokyo" test event series for next year's Olympic and Paralympic Games.

It gives the athletes and organisers the chance to see the venue in similar conditions to the Games, although surfing will be held slightly later at Tokyo 2020 than the test event.

Surfing competition at Tokyo 2020 is due to be held in a four-day window between July 26 and August 2.

It has been claimed that between late August and October is the best time to surf in Japan.

The surfing test event follows similar competitions in archery and weightlifting.