Givi Targamadze from the United National Movement (UNM), the largest opposition party, was in the front seat next to the driver when the blast occurred.
The driver also escaped unhurt but three passersby were slightly injured and two others were taken to hospital.
Georgia`s election pits the ruling Georgian Dream Party against the UNM, which lost a national election in 2012.
In other pre-election violence, two men were shot and wounded on Sunday at an open-air speech given by independent candidate and former defense minister Irakly Okruashvili in the town of Gori.
Opposition MP`s car explodes in Georgia`s capital, injuring passersby - VIDEO
05 October 2016
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A Georgian opposition lawmaker was unhurt when his car exploded in the capital Tbilisi on Tuesday but five passersby were injured, Rustavi-2 television reported, just three days ahead of a parliamentary election.
