Kadhim, who heads the Shura Council of the main opposition party al-Wefaq, was arrested last month after he posted a photograph on social media to protest at the process of parliamentary election in Bahrain, Bahrain’s al-Merat website reported.
Bahraini court has sentenced Kadhim to six month in prison and USD 8,000 in fines.
In the press briefing prior to his arrest, Kadhim told his followers to continue a "peaceful and civilized movement until victory" is reached, promising to continue his fight in prison.
Al-Wefaq has condemned Kadhim’s arrest as "security and judicial tools to punish opponents".
Human Rights Watch has called for the release of Kadhim as well al-Wefaq National Islamic Society Secretary General Sheikh Salman.
Salman has been under arrest since December last year on charges of inciting regime change. He denies the charges.
Bahrainis have been holding numerous protests in the past few days to mark the fourth anniversary of their uprising against the ruling Al Khalifa regime.
Demonstrators are seeking the downfall of the Al Khalifa regime and establishment of a democratically-elected government.
Amnesty International on Friday called on Bahraini officials to observe the citizens’ rights to freedom of expression and assembly ahead of the revolution’s anniversary.
Amnesty also slammed Bahraini authorities for the arrest of a number of opposition figures and activists, including the main opposition leader, Sheikh Salman.
Since mid-February 2011, thousands of anti-regime protesters have held numerous demonstrations on the streets of Bahrain, calling for the Al Khalifa family to relinquish power.
On March 14, 2011, troops from Saudi Arabia and the United Arab Emirates invaded the country to assist the Bahraini government in its crackdown on peaceful protesters.
Scores of Bahrainis have been killed and hundreds of others injured and arrested in the ongoing crackdown on peaceful demonstrations.
