Two South African soccer players have become the first athletes inside the Olympic Village to test positive for Covid-19, with the Tokyo Games opening on Friday.

Organisers confirmed the positive tests on Sunday but did not identify the athletes other than to say they were non-Japanese.

The South African Football Association (Safa) later confirmed there were three Covid-19 cases in its delegation - two players and a video analyst.

The players were defender Thabiso Monyane and midfielder Kamohelo Mahlatsi, Safa said.

The South African soccer squad had been quarantined and was waiting for the results of further tests conducted on players and backroom staff on Sunday, team manager Mxolisi Sibam said in a statement.

South Africa are due to play Japan in their first game of the men's soccer competition on Thursday at Tokyo Stadium.

Organisers also said on Sunday that another athlete had tested positive but this person was not residing in the Olympic Village.

This athlete was also identified as "non-Japanese".

Also on Sunday, the first International Olympic Committee member was reported as positive. He recorded a positive test on Saturday upon entering a Tokyo airport.

The International Olympic Committee confirmed the test and identified him as Ryu Seung-min of South Korea.

He won an Olympic gold medal in table tennis in the 2004 Olympics.

He was reportedly being held in isolation. Reports said he was asymptomatic.

IOC president Thomas Bach said last week there was "zero" risk of athletes in the village passing on the virus to Japanese or other residents of the village.

Former distance runner Tegla Loroupe, the chief of mission of the IOC's Refugee Olympic Team, has tested positive, two people with knowledge of her condition have told The Associated Press.

She tested positive before the team was to depart its training base in Doha, Qatar, for Tokyo. The team has delayed its arrival in Tokyo and many are expected to start arriving in the next few days.

Loroupe is expected to stay behind, according to the sources, who requested anonymity because they weren't authorized to reveal medical information.

Organisers say since July 1, 55 people linked to the Olympics have reported positive tests. This figure does not include athletes or others who may have arrived for training camps but are not yet under the "jurisdiction" of the organising committee.

The Olympic Village on Tokyo Bay will house 11,000 Olympic athletes and thousands of support staff.

Tokyo reported 1,008 new Covid-19 cases on Sunday, the 29th straight day that cases were higher than seven days previously. It was also the fifth straight day with more than 1,000 cases reported.

The Olympics will open on Friday under a state of emergency in Tokyo and three neighbouring prefectures. The emergency order lasts until August 22 and the Olympics close on August 8.

Fans - local and those from abroad - have been banned for all Olympic events in Tokyo and the three prefectures. A few outlying venues may allow a smattering of local fans.

About 200 protesters gathered on Sunday outside Shinjuku station in central Tokyo, waving signs that read "No Olympics".

It was the latest in a series of small protests over the past few months targeting the Games.

"We are not only protesting the Olympics," protester Karoi Todo told The Associated Press.

"We are opposing the government overall - this is ignoring human rights and our right to life. Infections are increasing. To do the Olympics is unforgivable."