UN leader Ban Ki-moon on Thursday called for political dialogue in the Maldives to overcome new tensions in the Indian Ocean state where the former president says he was ousted in a coup.

"The secretary general expresses his concern about the continued political tensions in the Maldives, which were manifested today in actions that impeded the opening of the Maldives' parliament," said UN spokesman Martin Nesirky.

Opposition MPs prevented the new president Mohamed Waheed from opening parliament and violent protests erupted outside the building.

Ban said the political crisis following the February 7 change of power "must be resolved peacefully through a national process and on the basis of dialogue and consensus."

"The secretary general urges all parties concerned to resume immediately their political dialogue," said his spokesman, "to find an agreeable way forward on the basis of the constitution and without jeopardizing the democratic gains achieved thus far in the Maldives."

Mohamed Nasheed says he was ousted by Waheed in a military-led coup on February 7 and called on its supporters to stage Thursday's demonstration against the new government.