King Hamad has set a November 22 date for Bahrain's first parliamentary elections since a Shiite-led uprising rocked the Sunni-ruled Gulf state in 2011.
The main Shiite opposition group Al-Wefaq, which made slender gains in the last poll held in 2010, withdrew its 18 MPs after a government crackdown the next year on Shiite protesters.
They were replaced in by-elections held later in 2011.
In a copy of a royal decree published on the official BNA news agency late Monday, King Hamad urged eligible voters to elect members of the 40-seat lower house of parliament.
The lower house has the authority to examine and pass legislation proposed by the king or cabinet and also has monitoring powers.
However, the upper chamber, or Consultative Council, appointed by the king and which has the same number of members, has the power to block legislation by the lower house.
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Bahrain's opposition, demanding a constitutional monarchy, has not yet announced if it will participate in the polls.
A proposal this month by authorities in the troubled kingdom to relaunch a national dialogue has been given a frosty reception by Al-Wefaq.
The proposal, unveiled on September 18, has five core elements, including the redefinition of electoral districts and parliament being permitted to question the premier and his ministers.
Parliament would also have a right of approval on the choice of ministers, and the authorities would commit to further judicial reform.
The security forces, meanwhile, would be bound by new codes of conduct.
The opposition is demanding an independent election commission, that the Consultative Council be dissolved, and the premier appointed by parliamentary majority, instead of the king.
Since a month of protests was forcibly repressed in March 2011, the opposition has taken part in two rounds of national dialogue. But it has withdrawn, saying the authorities were not making enough concessions.
Tiny but strategic Bahrain, home base for the US Fifth Fleet, remains deeply divided three years after the authorities crushed the protests.