"The scale of damage caused by cyclone Idai that hit the Mozambican city of Beira is massive and horrifying", the International Federation of Red Cross and Red Crescent Societies (IFRC) said in a statement.

It said 90 percent of the city of some 530,000 people and its surrounding area had been "damaged or destroyed"

"The situation is terrible. The scale of devastation is enormous," the IFRC's Jamie LeSueur was quoted as saying in the statement.

"Almost everything is destroyed. Communication lines have been completely cut and roads have been destroyed. Some affected communities are not accessible," he said.

A large dam burst on Sunday and cut off the last road to Beira, he said.

A toll compiled Monday by AFP from official sources puts the death toll in Mozambique at 73, including 55 in Beira alone, and 89 in Zimbabwe.

At least 150 more are missing in Zimbabwe, many of them believed to government workers whose housing complex was engulfed by floods.

Mozambique's environment minister, Celso Correia, warned that the death tally would rise.

"I think this is the biggest natural disaster Mozambique has ever faced. Everything is destroyed," he told AFP on Sunday night said at Beira international airport, which re-opened after being temporarily closed because of cyclone damage.

In Zimbabwe, Idai swept away homes and ripped bridges to pieces, leaving a trail of destruction that the acting defense minister, Perrance Shiri, said "resembles the aftermath of a full-scale war".

"There was a lot of destruction both on our facilities and on people," said Shiri speaking on television from the affected eastern highlands region.