Two people were killed carrying a homemade bomb and 20 unexploded bombs were discovered in Madagascar's capital at the weekend in suspected attacks that police blamed on former members of the island's administration.

Political turmoil has gripped the Indian Ocean island, which has oil, gold, uranium, nickel, cobalt and coal, since Andry Rajoelina overthrew Marc Ravalomanana's government in March to become Africa's youngest president.

Senior security officials said the spate of attempted bomb attacks in Antananarivo had connections with members of the former administration.

"There were five separate attempted attacks. Former state dignitaries are involved: a former minister, a former parliamentarian, a former ministerial secretary general and a former civil servant from the ministry of finance," Colonel Richard Ravalomanana told reporters late on Sunday.

One person suspected of preparing to plant a bomb was arrested, security force officials said.

Colonel Ravalomanana said the failed attacks targeted military posts and were aimed at destabilising Rajoelina, 35, and the interim government the former disc jockey established ahead of a promised election. No date for the poll has been set.

Madagascar has foundered in diplomatic isolation since Rajoelina's power-grab, but his grip on power has strengthened with time.

The crisis has alarmed major foreign companies developing the island's resources, stunted economic growth and threatened the $600 million-a-year textile sector.

Source: Reuters