Mohammad Iqbal, an official at the anti-trust agency, and businessman Billy Sindoro, were detained at a luxury hotel in the capital Jakarta on Tuesday, Antasari Azhar, the head of the Corruption Eradication Commission, known as KPK, told reporters.
"A KPPU member has been caught red-handed receiving 500 million rupiah from a businessman," said Azhar, who referred to the two men by their initials.
Separately, a deputy chairman of KPK told a news conference that Iqbal and Sindoro had been declared suspects after more than 14 hours of questioning.
"After KPK conducted interrogations from last night until today, both have been declared suspects and we will hold them for 20 days," Chandra Hamzah told reporters.
Hamzah said the alleged bribe was suspected to be related to a monopoly case involving Direct Vision, partly owned by First Media
Anti-trust official Iqbal could not immediately be contacted, but a lawyer representing him said he would meet his client on Wednesday to discuss the case.
A spokesman for KPPU said it was the first such case involving the agency since it was founded eight years ago.
"Hopefully this case will be the first and the last," said spokesman Ahmad Junaidi.
Iqbal was a member of the anti-trust agency's commission that ruled in August that Direct Vision had not violated Indonesia's anti-monopoly law in a case related to TV broadcast rights for the English Premier League, according to KPPU's web site .
Businessman Sindoro, a former president of First Media, could not immediately be contacted.
A company aide to Sindoro could also not be reached, while a corporate secretary at First Media declined to comment on the case, saying that Sindoro was no longer president.
Since coming to power four years ago, President Susilo Bambang Yudhoyono has pledged to tackle graft.
Many high-ranking Indonesian officials, parliament members, bankers and executives have been jailed, although critics say some of the worse cases of graft have yet to be tackled.