JOHANNESBURG (Reuters) - Madagascar's government has halted air links with neighbouring Mozambique, stranding senior Malagasy negotiators in Maputo where they had struck a deal on a unity government, the talks' mediator said on Wednesday.

Madagascar's President Andry Rajoelina, who grabbed power in a March coup, rejected on Tuesday the agreement on the make-up of the unity government that was struck by his rivals in Mozambique, and said it was tantamount to a coup d'etat.

Former Mozambican President Joaquim Chissano, who mediated the talks, told Reuters that a number of the negotiators had been prevented from returning home.

"It's true ... the government of Madagascar has interdicted the plane which should have come to collect them from Maputo and they have also interdicted any other flight from Maputo to Antananarivo," he said.

Chissano was speaking by telephone from London where he flew after the Maputo talks.

Among those stranded in Maputo are former Malagasy President Albert Zafy and Prime Minister Eugene Mangalaza, who was put in office by Rajoelina under international pressure.

Zafy shook hands on the division of senior cabinet posts and a timetable for setting up transitional institutions with two other former presidents of Madagascar, Marc Ravalomanana and Didier Ratsiraka, who both live in exile.

International mediators have brokered several power-sharing agreements with Madagascar's feuding politicians in recent months but all have come unstuck.

Chissano said he did not understand why Rajoelina was not willing to discuss Tuesday's deal, especially as parts of the proposal followed requests made by Rajoelina himself.