Bahrain opposition party Al-Wefaq National Islamic Society said the participation rate in Saturday's parliamentary and local council election from which opposition groups have been barred did not exceed 30 per cent.
"According to monitored figures and information; the participation rate was only 28 per cent and 30 per cent," said Deputy General-Secretary Sheikh Hussein Al-Daihi.
"We challenge the authorities to reveal with complete transparency the elections results," he added.
The organisation wrote on Twitter that "the elections were widely boycotted and there was a low voter turnout".
Bahrain's Minister of Justice, Khalid Bin Ali Al Khalifa, said on Saturday that the voter turnout reached 67 per cent, more than the 53 per cent recorded in 2014 when the opposition groups boycotted the elections.
"The ballot box received the largest number of votes in the history of Bahrain, and this is the largest number participating in the elections," he said.