"There have been heavy downpours over the past 24 hours," Alex Mdooko, commissioner of Chikwawa, a district in Malawi's southern region, told The Anadolu Agency by phone on Thursday.
"We have had two nights of rain and, so far, vast pieces of land are in water again," he said.
Heavy rainfall has caused fresh flooding in Chikwawa and Nsanje, another southern district.
"The Shire River has taken in more water to overflow again," said Mdooko. "We have yet to assess the extent of the damage."
He asserted that the fresh wave of floods would make life difficult for many displaced people, who are now housed in temporary shelters and relief camps.
Malawi suffered prolonged heavy rains in early January, leading to unprecedented flooding in the country's southern and eastern districts.
President Peter Mutharika said recently that his government was seeking $81 million to support affected populations.
New figures by the United Nations Disaster Assessment and Coordination (UNDAC) have revealed that twice as many people had been affected and displaced by the flooding than had been originally thought.
It said that 336,000 had been displaced by the flooding, up from initial estimates of some 200,000, while more than one million had been affected, up from initial estimates of some 638,000.
UNDAC estimated that some 276 people had been killed while hundreds more had gone missing.
"With these new numbers, and while prioritising additional severely affected districts, we need to take stock of our response to ensure all children and families have access to emergency services and supplies," Mahimbo Mdoe, UNICEF's representative in Malawi, told reporters on Thursday.
"We are carefully monitoring how displaced children are faring, as we know after one month in crowded camps disease outbreaks and increased malnutrition can occur," he said.
"With rains still falling in the area, many of those displaced have gone to ad hoc camps and evacuation centers and are still unable to return home," the UNICEF official noted.
The floods have disrupted education for more than 300,000 students, as many schools have been occupied by displaced families.
Malawi's Department of Surveys had earlier estimated that, as of Jan. 13, 63,531 hectares of land had been inundated by floodwater.
It is estimated that around 116,000 of the nation's farmers – and some 35,000 hectares of cropland – have been affected.