Sri Lanka has closed government offices and schools as the death toll from floods and landslides across the country has risen to 56, with more than 600 houses damaged, according to officials.

Sri Lanka began grappling with severe weather last week, and the conditions worsened on Thursday with heavy downpours that flooded homes, fields and roads, and triggered landslides across the country.

At least 193 people have been confirmed dead across Sri Lanka as authorities continue to battle rising floodwaters in parts of the capital after a powerful cyclone left a trail of destruction.

More heavy rains brought on by Cyclone Ditwah are expected across the island nation in the coming days, the Disaster Management Centre (DMC) said on Sunday, adding that more than 220 people remain missing.

The death toll from extreme weather conditions in Sri Lanka has risen to 410, while 336 people remain missing, the country's Disaster Management Center said on Tuesday.

The cyclone's has affected than 1.4 million people across 25 districts, turning homes into rubble and forcing thousands into shelters.

Landslide warnings were still being issued in Sri Lanka in the wake of last week's Cyclone Ditwah, with the death toll from the floods jumping to 607.

Some 214 people remained missing, the Disaster Management Center said. Many of those previously unaccounted for were now presumed dead.

The death toll from floods and landslides on the Indonesian island of Sumatra island has risen to 174, up from the previous 94, the country's disaster mitigation agency said on Friday, adding that dozens remain missing.

A total of 303 people died and 279 remain missing after flash floods and landslides struck three provinces in Indonesia's Sumatra region, the country's National Disaster Management Agency (BNPB) said on Saturday, Xinhua reports.

BNPB Chief Suharyanto told a press conference that North Sumatra suffered the highest number of casualties, with 166 deaths and 143 people still unaccounted for. In West Sumatra, 90 people were confirmed dead and 85 missing, while in Aceh, 47 fatalities were recorded and 51 people remained missing.

The number of people killed by floods and landslides on Indonesia's Sumatra island rose to 708 on Dec 2, the disaster agency said, as authorities rushed to repair infrastructure and deliver aid to cut-off areas.

The agency in a press conference late on Dec 2 said 708 people had been killed since last week, a figure lower than the 753 reported on its website earlier in the day. It did not give a reason for the discrepancy.

Close to 900 people have been killed in floods and landslides that have wreaked havoc in Indonesia, Malaysia and Thailand, which follow months of adverse and deadly weather in South-east Asia, including successive typhoons that struck the Philippines and Vietnam and added to frequent and prolonged flooding elsewhere.

Residents in Indonesia's Aceh Tamiang district were forced to scramble over fallen trees and wrecked vehicles on Saturday (December 6) as they made a gruelling hour-long walk to reach emergency supplies, with the death toll from this month's devastating floods and landslides on Sumatra now exceeding 900.

Cyclone-driven downpours have triggered floods and landslides across three provinces on Sumatra, including Aceh, killing 908 people and leaving 410 still unaccounted for, according to government figures released on Saturday.

The same storm systems have also claimed about 200 lives in southern Thailand and Malaysia.