A spokesman for the National Front party said campaign boss Qabil Mamedzayev had been detained.
Its partner in the main opposition bloc, the Democratic Party, said earlier its own campaign manager, Faramaz Javadov, had been arrested by plainclothes police in a raid on the party's campaign headquarters late yesterday during which party leaflets were also confiscated.
Police have confirmed neither arrest.
Both the National Front and the Democratic Party are part of the Azadliq bloc, seen as the strongest opposition force contesting the election.
Polls predict the ruling Yeni Azerbaijan Party will comfortably regain its massive majority in parliament. But Western officials say they are concerned about how the vote is conducted.
Azerbaijan Election Special
A photo gallery of the Azerbaijan opposition protests in Baku on November 9, 2005.