Wednesday's explosions in the eastern city of Constatine continued the violent run-up to the vote after three suicide bomb attacks killed 33 people in the capital, Algiers, on April 11.
A police officer was killed and five other people were injured in the country's third-biggest city, Constantine, 48 hours after al-Qaeda called on Algerians to boycott the polls en masse.
There have been fears that the recent attacks will prompt a return to the levels of violence experienced in the 1990s.
The poll to choose the 389 members of the lower house of parliament is the third since a revolt follwed the cancellation of a national election in January 1992, which a now-outlawed party was poised to win.
Rubber stamp
Political analysts say that with power in Algeria concentrated in the hands of Abdelaziz Bouteflika, the president, whose mandate ends in 2009, many Algerians have little interest in parliament and may, therefore, not bother to vote anyway.
Algerians tend to believe the assembly exists to rubber stamp the decisions of the executive branch.
Social problems are Algerians' main concern, with unemployment among adults under 30 at 75 per cent.
The National Liberation Front (FLN), is expected to keep its position as the largest single party, with the pro-government Rally for National Democracy (RND) likely to take second place.
The FLN and RND are part of a ruling coalition with the Movement of Society for Peace (MSP).