Madagascar's opposition on Wednesday vowed to defy an official ban and go ahead with a weekend protest over "scandalous" new election laws ahead of elections in late 2018.Opposition MPs unanimously approved the plan to protest on Saturday outside city hall in the capital Antananarivo, said lawmaker Hanitriniaina Razafimanantsoa of TIM, the country's second largest opposition party.Local authorities had declared the protest illegal on Tuesday, with the prefect of Antananarivo, Angelo Ravelonarivo, saying the organisers had submitted a "notification" instead of the required "request for authorisation".Razafimanantsoa said the prefect had acted on orders from the government of the former French colony off the southeast coast of Africa. The opposition accuses the government of President Hery Rajaonarimampianina of wanting to muzzle it ahead of presidential and legislative elections to be held in late November or December. Opposition MPs charge that three new recently adopted laws favour the ruling party. Elected in 2013, Rajaonarimampianina has not yet announced whether he will stand for re-election.Meanwhile two former heads of state have already mooted runs: Marc Ravalomanana, who was president from 2002 to 2009 and is backed by the TIM, and Andry Rajoelina, who succeeded him.Both were barred from running in 2013. Ravalomanana was overthrown in 2009 after an army mutiny that allowed Rajoelina - then Antananarivo mayor - to become the country's unelected transition president until 2014. Rajaonarimampianina's arrival in power brought an end to a long series of political crises in the country.* Sign up to News24's top Africa news in your inbox: SUBSCRIBE TO THE HELLO AFRICA NEWSLETTERFOLLOW News24 Africa on Twitter and Facebook.