Ulrich Rodrigue Yombo failed to appear at the weigh-in on Wednesday ahead of the quarter-final bout in the 81kg division, gifting Canadian boxer Harley O'Reilly a bronze medal by virtue of a default semifinal place.

Yombo's disappearance came after it was revealed five Cameroon athletes have gone missing from the village since the Games began last week.

Weightlifter Olivier Matam, and boxers Ndzie Tchoyi and Simplice Fotsala had been due to compete on Tuesday but could not be found, Cameroon team manager Victor Agbor Nso told Cameroon state media.

Two other weightlifters, Aka Angeline Filji and Mikoumba Petit David, had earlier gone missing from the Games, but he did not specify when.

Cameroon's Ministry of Sports and the president of the National Olympic Committee of Cameroon have been informed, Nso said.

"We have also laid a formal complaint to the Australian police," he told Cameroon state broadcaster CRTV.

Weightlifter Olivier Matam is one of six Cameroon athletes said to have gone missing from the 2018 Commonwealth Games. Dean Mouhtaropoulos/Getty Images

It is not the first time Cameroonian athletes have disappeared at a major sporting event. In 2012, five male boxers, a female footballer and a male swimmer absconded from the London Olympic village.

Games organising committee chairman Peter Beattie said at this point in time none of the athletes had breached Australian law.

"This happens at every games, it's no surprise ... if there is a breach (of visa) Peter Dutton and his team will deal with it," Beattie said.

Commonwealth Games Federation chief executive David Grevemberg said his organisation was monitoring the situation but until the missing Cameroonians broke Australian law it was a matter for them and their team officials.

"It's obviously disappointing that some of the athletes that have come, didn't compete," Grevemberg said.

"Until it becomes a real issue in terms of visas and so forth we would obviously need to take that very seriously but right now it's a safety and welfare issue for those athletes from a Team Cameroon perspective."