A powerful bomb explosion rocked the Athens southern suburb of Glyfada before dawn on Wednesday, in the heart of the area's commercial centre, causing extensive damage to shops but no injuries.

The explosion, which occured at 4.08am according to reports, destroyed dozens of shops along Glyfada's main commercial street and blew out windows of apartments within a 100m radius.

The Celestino boutique, outside which the explosion occurred, was completely demolished, while more than 20 other shops suffered extensive damage.

The bomb left a crater about 30 centimeters deep on the pavement, and police said there were no victims because of the very late hour.

The explosive device contained up to 10kg of explosives, according to initial estimates by police.

The motives for the attack are as yet unknown, and police are examining all possibilities, but believe it was most likely carried out by an extortionist ring.

The area has been cordoned off until completion of the crime scene investigation.

Unconfirmed reports said security camera footage from shops and banks showed a man on a motorcycle stopping and putting down a paper bag on the street outside the boutique.

All possibilities were being examined by police.