The deaths in floods and landslides caused by the heavy rainfall that began last week in Sri Lanka have mounted to 146 while 112 other people have been reported missing, the Disaster Management Centre (DMC) said on Sunday.

The DMC said in its latest situation report that 442,299 people have been affected by the rains in one way or another in 15 of the country's 25 districts, Efe news reported.

On Sunday, the rainfall eased somewhat, although it is expected to intensify again from Monday.

In addition, 101,638 more people had to be evacuated, the DMC added.

Water levels in rivers in the districts of Hambantota and Ratnapura have begun to fall, but in other places such as the Nilvala river, levels are on the rise, DMC spokesperson Pradeep Kodippili, told Efe news.

"We were able to evacuate the people in the surrounding villages and towns on time last night," added Kodippili, referring to Nilvala river, which rescue workers were trying to contain with sand bags.

The number of troops engaged in emergency work has increased to 1,700.

The authorities were preparing to deploy military transport vehicles to assist in evacuation in the affected areas, army spokesman Brigadier Roshan Senevirathne said.

The areas of Kalutara, Galle and Mataro -- traditional tourist destinations -- are among the worst affected.

The Sri Lankan government has called on the international community to provide financial aid and logistical support.

Heavy seasonal rains -- which this year came after one of Sri Lanka's worst droughts in 50 years -- often hit the island nation hard at this time of year, generating uncertainty in the agricultural sector, a major source of resources in the country. 

The first vessel with humanitarian aid from India reached Colombo on Saturday. A second vessel will arrive later on Sunday.