Demonstrations have been held during the three-day Grand Prix event every year since 2011 by opponents of the ruling Sunni Al-Khalifa dynasty in an attempt to highlight pro-reform demands.
The protests, which first erupted in the wake of a Shiite-led uprising in February 2011, have at times been marred by violence but the race has never been affected.
They are mainly staged in Shiite villages surrounding Manama and away from the Sakhir F1 circuit in the capital's south.
Al-Wefaq in a statement today urged its supporters to hold a rally on the main Budaya highway, four kilometres west of Manama, which links several Shiite villages.
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Al-Wefaq's peaceful rallies are usually tolerated by the authorities and rarely end with clashes.
But protests by supporters of radical cyber-group the February 14 Revolution Youth Coalition are more violent and often end with clashes between police and demonstrators armed with petrol bombs.
The February 14 group, accused by authorities of links to Shiite-majority Iran, called on its Facebook page for demonstrations today in the Al-Seef Junction area, west of Manama, under the slogan: "Stop the blood formula."
The rallies have been broken up by police firing tear gas and stun grenades, with protesters hurling petrol bombs and throwing stones, according to witnesses.
Public security chief General Tariq Hasan said today the authorities have taken "all measures and plans" to secure the April 4-6 Formula One event.
Police will deploy around the Sakhir circuit and along main roads leading to it, the official BNA news agency quoted Hasan as saying.
"There are fears that the authorities may use recent unrest, including terror attacks on police, to justify imposing further restrictions during the Grand Prix," said the London-based human rights watchdog.