Bahraini security forces arrested Sheikh al-A'ali on charge of supporting prominent Shiite cleric Sheikh Isa Qassim, Beirut based Al-Manar TV reported.
The development comes as Bahrain has been witnessing massive rallies in support of Sheikh Qassim, the spiritual leader of Shiites in the country.
The Al Khalifa regime announced on June 20 that the citizenship of Sheikh Qassim has been revoked, accusing him of sowing sectarian divisions.
The regime later said it would put the senior cleric on trial on charges of "illegal fund collections, money laundering and helping terrorism."
Bahrain, a close ally of the US in the Persian Gulf region, has been witnessing almost daily protests against the ruling Al Khalifa dynasty since early 2011, with Manama using heavy-handed measures in an attempt to crush the demonstrations.
Scores of Bahrainis have been killed and hundreds of others injured and arrested in the ongoing crackdown on the peaceful demonstrations.
Amnesty International and many other international rights organizations have frequently censured the Bahraini regime for the rampant human rights abuses against opposition groups and anti-regime protesters.