"The term of sentence on four charges against Sheikh Ali Salman might be up to 19 years," Shamlawi was quoted as saying by the Bahraini daily newspaper Al-Wasat.
On December 28, 2014, Salman was arrested in Bahrain's capital Manama on charges of inciting "a violent regime change through illegal practices and publicly insulting the Interior Ministry."
His arrest led to mass protests in Bahrain, as Shiite opposition supporters held rallies demanding Salman's release.
On Monday, Bahrain's Public Prosecution announced that the date of the court trial was scheduled for January 28.
Al-Wefaq led anti-government protests which began in Bahrain in 2011 during the Arab uprising. Shia Muslims, who form a majority in Bahrain, initiated the protests to achieve greater political freedom and equality as they says the regime under the Sunni Al Khalifa royal family infringes upon their rights.
After the crackdown on protest rallies by the authorities, Shia opposition deputies left parliament and boycotted last year's elections.
Yesterday regime forces attacked protesters demanding the release of a prominent Bahraini opposition figure.
The protesters were demanding the release of Sheikh Ali Salman, the secretary general of the country's main opposition bloc, al-Wefaq National Islamic Society.
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click and Watch Clashes between activists and police and Rajab's comments
In a separate development, prominent Bahraini human rights activist Nabeel Rajab has been found guilty of insulting government ministries on Twitter and sentenced to six months in jail.
The Bahraini authorities must quash the conviction of prominent human rights defender, Nabeel Rajab, who has today been sentenced to six months in prison for posting comments online which were considered insulting to the Ministries of Interior and Defence, Amnesty International said.
“Nabeel Rajab is being unjustly punished simply for posting tweets deemed insulting to the authorities. His conviction is a blow to freedom of expression – it must be quashed. He should be released immediately and unconditionally,” said Said Boumedouha, Deputy Director of Amnesty International’s Middle East and North Africa Programme