Indonesia's anti-corruption agency has detained a Constitutional Court judge in connection with a graft investigation, the court's chief justice said on Thursday.

Chief Justice Arief Hidayat said the judge, Patrialis Akbar, would be suspended from duty and possibly sacked if found to have violated the law.

"We will request permission from the president to suspend the judge first and permanently relieve him of his duties if there has been a violation of the law," Hidayat told a news conference.

"We feel very concerned that this has happened," he said, referring to what he described as an "operation" by the Corruption Eradication Commission (KPK) to detain Akbar.

Neither Akbar nor his lawyer were available for comment. An assistant to Akbar declined to comment.

A public relations official at the KPK also declined to comment.

The Constitutional Court, once regarded as a model of integrity in Indonesia's notoriously corrupt judiciary, has been rocked by bribery scandals in recent years.

Its former chief justice was in 2014 sentenced to life in prison for accepting bribes and money laundering in connection with an election dispute. It was the heaviest sentence ever handed out for graft in Indonesia.

The court hears cases regarding election disputes and challenges to laws.

Akbar was detained in relation to his role in hearing a judicial review of the animal and livestock health law, media reported.

Hidayat said the court had not been given details of the investigation but remaining judges would cooperate fully with the KPK.

The judicial review of the livestock law would not be affected by the investigation and a verdict would be announced soon, he said.

Akbar, one of nine Constitutional Court judges, was appointed to the court in 2013 by former president Susilo Bambang Yudhoyono. He had served as minister for law and human rights in Yudhoyono's administration.

The KPK is popular among ordinary Indonesians for targeting members of the establishment suspected of abusing their positions in a country where people frequently have to pay bribes to get basic services.

Graft in Indonesia is cited as a deterrent to more foreign investment in Southeast Asia's biggest economy.

Global watchdog Transparency International this week ranked Indonesia 90 out of 176 countries in an annual survey that looks at public perceptions of corruption in a society. The ranking places Indonesia on par with countries including Liberia and Colombia.