Rescue workers in Indonesia are continuing to battle to reach victims in several devastated areas submerged by cyclone-driven torrential rain over the past week, as authorities said the death toll has now reached 303 and would likely continue to rise.

Indonesia’s National Disaster Management Agency (known as the BNPB) said on Saturday that the number of confirmed casualties following this week’s catastrophic flooding and landslides now stands at 303, with more than 100 people still missing, after rescuers in West Sumatra’s Agam district recovered more bodies.

More than 500 people have also been injured, the BNPB said.

“The death toll is believed to be increasing, since many bodies are still missing, while many have not been reached,” said Suharyanto, head of the BNPB, who, like many Indonesians, only uses one name.

Updating an initial death toll of 23 for the whole province of Sumatra, West Sumatra Regional Disaster Mitigation Agency spokesman Ilham Wahab said late on Friday that 61 people had died and 90 were missing.

“A total of 75,219 people have been displaced, and a total of 106,806 people have been affected throughout West Sumatra,” Ilham said.

A further 116 people were later confirmed killed in North Sumatra, while in Aceh province the death toll had reached at least 35 people, according to figures released by authorities.

Swaths of Indonesia, Malaysia and Thailand have been inundated with days of torrential rain – killing about 400 people across the three countries in total – after a rare tropical storm formed in the Malacca Strait between the Malay Peninsula and the Indonesian island of Sumatra.

At least 145 people were confirmed killed across Thailand’s eight southern provinces as of late Friday, while more than 3.5 million people have also been affected by floodwaters. Two people have been killed in neighbouring Malaysia.

While the torrential rain finally let up late on Friday, in Indonesia, many people remain missing and thousands of families have been displaced.

The heavy downpours caused rivers to burst their banks in Indonesia’s North Sumatra province, with the deluge tearing through mountainside villages, sweeping people away and submerging thousands of homes and buildings.

Badly hit areas have been largely cut off from rescue teams by damaged roads and downed communications lines, with relief efforts also hampered by collapsed bridges, flooded roads and a lack of heavy moving equipment.

Relief aircraft continue to work to deliver aid and supplies to the hard-hit district of Central Tapanuli in North Sumatra province and others in the region.