Khalil al-Marzoug, one of Shiite opposition leaders announced the movement's consent late on Friday after 11th-hour deliberations to take part in the the national diaolgue coming in the wake of a deadly March crackdown on Shiite-led protests, the Manama daily Al-Wasat reported.
Al-Wefaq's five-strong delegation will maintain the group's demand that in future the prime minister be drawn from the majority bloc, Marzoug said.
Incumbent Prime Minister Sheikh Khalifa bin Salman al-Khalifa, an uncle of King Hamad, has been in office ever since independence from Britain in 1971 and is widely despised by the opposition.
"We do not intend to sabotage the dialogue but we do intend to bring to it the demands of the people," Marzoug was quoted as saying.
Tiny but strategic Bahrain, the home base of the US Fifth Fleet, has experienced repeated bouts of unrest between its Shiite majority population and the Sunni ruling family.
The government's crackdown on Shiite-led protests which broke out in February, was backed by troops from its Gulf neighbours and left 24 people dead.
Al-Wefaq had threatened not to take part in the dialogue in protest at being invited to choose just five out of the 300 delegates, even though it took a majority of the vote at the last parliamentary elections winning all 18 seats which it contested in the 40-seat lower house.
Its 18 MPs all tendered their resignation in March in protest at the government's deadly crackdown.
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