Madagascar’s electoral court has declared former Finance Minister Hery Rajaonarimampianina president-elect, an outcome his defeated rival swiftly rejected.

The Friday ruling sustained the result of the December 20 vote, the first since a coup on the Indian Ocean Island in 2009.

“I urge goodwill from everyone so that we can build a prosperous and stable nation,” said Rajaonarimampianina, who was backed by the outgoing president, Andry Rajoelina, who spearheaded the 2009 overthrow of Marc Ravalomanana.

His opponent, Jean Louis Robinson, who alleges widespread rigging of the vote, said he would not accept the result and would continue to challenge the outcome.

“We contest the court’s decision in the strongest way,” he told reporters, after boycotting the formal announcement.

The electoral court said Rajaonarimampianina won 53.5 per cent of the vote to Robinson’s 46.5 per cent, confirming the electoral commission’s provisional results.

Robinson, who was backed by Ravalomanana, said he would not yet be calling on his supporters to protest on the streets of a country that has seen years of political turmoil, sometimes violent.

He plans to outline the vote’s “irregularities” to the Southern African Development Community and African Union. Both blocs had worked on a political deal to push Madagascar towards an election.

A drawn-out dispute is likely to stir up further the nickel-producing island’s volatile political scene and could delay restoring the external budget support needed to spur public spending and growth.