Vietnamese officials say that more than 50,000 houses are still submerged along an area from northern Nghe An province to Gia Lai province in the south, covering roughly 1,000km, with rivers in some areas expected to peak on Thursday.
The National Flood and Storm Control Committee said at least 42 people were killed in Vietnam by the storm or swept away by floods in its aftermath.
Seven were missing and 502 injured.
Although rains had stopped in most central provinces by Tuesday, heavy rains continued on Wednesday in the provinces of Ha Tinh and Nghe An, unleashing floods that caused some of the newly reported deaths, officials said.
Phan Nguyen Tung, a disaster official in Ha Tinh province, said rivers in the province were still rising slowly and were expected to rise further on Thursday.
The national government announced it will provide 1,500 tonnes of rice and $3.1 million to the victims.
More than 200,000 people were evacuated before the typhoon and that has helped to minimise casualties, officials have said.
Initial estimates of damage were about $623 million.
Officials in the Philippines have said that the toll had risen to 110 from 78 on Monday.
The toll has raised to 110 in
At least 88 people were injured and a further 79 were still missing.
Properties worth about $58 million were damaged by Xangsane, which means "elephant" in the Lao language.
The typhoon's fierce winds and rain destroyed or damaged hundreds of thousands of homes when it slammed into Vietnam's central coast on Sunday after bringing parts of the Philippines, including the capital Manila, to a standstill last week.