At least 49 people were killed this weekend in landslides caused by torrential rains in rural Rwanda, the government said on Monday.

Authorities had previously given a death toll of 20, many of them children, as downpours drenched the densely populated country of steep hills and deep valleys.

"During the night of 7-8 May 2016, heavy rains caused landslides in several parts of Rwanda, resulting in loss of lives, and destructing of homes, infrastructure and other property," a statement said.

The worst affected district was Gakenke in the north, where 34 people were killed, with another 15 dead and 26 injured in western parts of the country.

"Over 500 houses were completely destroyed and various roads sections rendered unusable," the government said in its statement.

Landslides are not unusual in Rwanda but this year's rainy season has been particularly deadly with at least 67 people killed from January to April.

Of that total, 12 people died on a single night in the suburbs of the capital Kigali, where 1,500 homes were damaged during rainstorms.

Authorities blame the El Nino weather phenomenon for the disasters.