(AFP) - Madagascar's top court on Thursday ordered that presidential elections be postponed by one week, amid high political tensions after disputes over the regularity of the vote.

For more than a week, opposition parties have held demonstrations against what they call an "institutional coup" to keep outgoing president Andry Rajoelina in power.

"The Constitutional Court, by virtue of its regulatory power, orders the postponement of the first round of the presidential election to November 16, 2023," the court wrote in a ruling.

Voters in the Indian Ocean island nation were initially due to head to the polls on November 9.

The ruling follows an appeal filed by a presidential candidate, who was injured at one of the protest rallies that have routinely been dispersed by police.

Andry Raobelina had asked for the vote to be postponed citing "force majeure" after he suffered a face injury as police fired tear gas on demonstrators earlier this month.

He later sought medical attention in the nearby island of Mauritius.

The court dismissed his appeal, saying the risk of injury was foreseeable as the protest had not been authorised but ordered the government to issue a decree to move the day of the vote in any case.

This was in line with constitutional principles aimed at guaranteeing fair, transparent and peaceful elections, including the granting of equal opportunities to all candidates, the judges wrote.

The date for a potential second round on December 20 was kept unchanged.

- Political crisis -

It was the latest twist in a political crisis that has gripped the country since Rajoelina, 49, resigned last month in line with the constitution in order to run for re-election.

The president of the Senate, Herimanana Razafimahefa, was supposed to take over but declined for "personal reasons", leaving the task to a "collegial government" headed by the prime minister, an ally of Rajoelina.

The move was accepted by the Constitutional Court, which also dismissed appeals to have Rajoelina's candidacy declared void over his dual French nationality, sparking opposition anger.

Eleven out of 13 opposition candidates have since led almost daily, unauthorised marches in the capital, Antananarivo, which have been met with a heavy police presence.

This week, Razafimahefa sent a letter to the Constitutional Court walking back on his decision to turn down the caretaker role, telling journalists he had faced "pressure" to step aside but was now ready to assume his responsibilities.

But on Thursday, senators voted to dismiss him from his post during an extraordinary sitting after lawmakers from the ruling party questioned his mental health state.

Rajoelina first took power in 2009 on the back of a coup.

After not running in the 2013 election due to international pressure, he was voted back into power in 2018.

He has since held the reins in a country that remains among the poorest in the world despite vast natural resources.

This week, he launched his re-election campaign telling thousands of supporters who gathered in the capital, Antananarivo: "No one will take the victory away from us."

He had earlier accused his opponents of creating a political crisis "from scratch" because they were "not ready" for the vote.

The United Nations on Tuesday expressed concern over the "deteriorating human rights situation" in Madagascar in the runup to the polls after "unnecessary and disproportionate force" was used to disperse protests.

© Agence France-Presse