Polls opened on Saturday to choose 293 candidates for parliament in the kingdom that has been hit by ongoing unrest since 2011, when security forces crushed protests demanding elected leaders.
The country's two main opposition groups, the Al-Wefaq and Wa'ad, were barred from fielding candidates and they called for a boycott of the elections which they have described a "farce", Presstv Rported.
International rights groups and experts have questioned the value of a parliamentary election in which the opposition is not allowed to participate.
Amnesty International on Friday expressed “grave concerns” over a campaign of suppression by the ruling Al Khalifah regime against political dissidents and pro-democracy activists.
“Over the past two years, the crackdown in Bahrain has seen the political opposition detained, intimidated and silenced,” Devin Kenney, the rights group's Bahrain researcher, said in a statement.
At least six people were detained and charged this month for "obstructing the electoral process," according to statements released by Bahrain's Public Prosecutor.
One of them was Ali Rashed al-Asheeri, a former member of parliament with al-Wefaq, who was arrested after tweeting that he and his family would not be voting.
Since February 2011, Bahraini people have been holding peaceful protest rallies on an almost daily basis, demanding that the Al Khalifah family relinquish power and allow the establishment of a just system representing all Bahrainis.