PSS Sleman and PSIS Semarang could be relegated from the Indonesia Super League's premier division after scoring five own goals in a match to decide their opponents in the playoffs, the country's football association (PSSI) said.
Hinca Pandjaitan, the chairman of the PSSI's disciplinary committee, said the teams had been disqualified from the competition and that they could expect even tougher sanctions if evidence of matchfixing was uncovered.
The incident is the latest blow to football in Indonesia, where warring factions left the country with two national teams and two domestic leagues at one point in 2012.
World governing body FIFA threatened the Southeast Asian nation with suspension unless they sorted out the problems and a truce was eventually reached with the leagues, national teams and separate football associations agreeing to unite.
"They have breached the basic principle of football, which is to keep the sportsmanship and integrity of the sport," the Jakarta Globe quoted the committee chairman as saying.
"We will hold further investigation and examine all players, coaching staff and officials ... Should we find any evidence (of matchfixing), they will receive another sanction.
"Both clubs may be relegated from the premier division. First we have to make a decision on their current status in order to save the competition."
The clubs met in their final Group 1 match on Sunday with the winners set to play Group 2 runners-up Pusamania Borneo FC in the semi-finals.
The newspaper reported that PSS scored the first own goal in the 78th minute, then another shortly after to give their opponents a 2-0 lead.
However, PSSI then scored three own goals of their own, to leave PSS with the 3-2 win.
PSS manager Soepardjiono denied accusations that the own goals were intentional.
"We never planned to make those own goals," he said. "We're not afraid to play any team from Group 2 in the semi-finals."
Komaedi, who scored two own goals for PSIS, said: "I was confused, so were my team mates. We couldn't think clearly in the match. Things got worse as the fans provoked us after PSS made two own goals."
The match referee, Hulman Simangunsong, said he had no option but to let the teams play on.
"If I stopped the match, it would be the official result anyway because the referee can't change match results or declare the match voided," Hulman said. "Besides, there's no violation of match regulation."