Prapiroon - aptly named after the Thai god of rain - had killed 57 and another 16 were missing, the China News Service said, citing preliminary statistics from local governments.
"It's still raining heavily, and the situation is pretty serious," an official told AFP from the flood control headquarters in Guangxi region, where the eye of the storm was located early on Sunday.
In densely populated Guangdong province, so far the most severely affected part of China, the death toll stood at 38, with another 14 missing, according to the news service.
In Guangxi, immediately to the west of Guangdong, 19 were confirmed killed while two were missing, it said.
Tragedy struck in Luming, a hamlet in a mountainous part of Guangxi, when a landslide engulfed the home of a family of four, killing three of them, a local official said.
"Only one man survived," said Qin Jiexia, a spokeswoman of the flood control official in Heng county, where Luming is located.
"He lost his wife, his daughter, and his sister-in-law."
In Fenghuang township, also part of Guangxi, at least six farmhands died when early on Saturday a flood swept away the temporary shelter they had built for the night to stay dry, state-run Xinhua news agency said.
Although Prapiroon had now been downgraded from a typhoon to a tropical storm, it continued to impact the lives of millions of people.
The storm continues to impact
the lives of millions of people
A total of 6,400 houses had been toppled by landslides and floods, and crops on 172,00 hectares (425,000 acres) of farmland had been destroyed, according to the agency.
Prapiroon was southern China's sixth typhoon of the season, which started more than a month earlier than usual with Typhoon Chanchu. It made landfall on May 18.
More than 1,400 people have been killed in China due to typhoons this season, according to the Red Cross, which this week appealed for 3.8 million euros (five million dollars) to help survivors.
Another 16 people were reported killed in floods triggered by heavy monsoon rains in southern India on Sunday, taking the toll in the past five days to 62, officials said.
The Godavari River in Andhra Pradesh rose three metres above the danger mark, prompting authorities to move about 14,000 families to relief camps, the Press Trust of India quoted unnamed officials as saying.
More than a dozen helicopters, naval boats, and many small mechanised boats were pressed into service to rescue people.
Unrelenting rains also lashed western Maharashtra state, where 15 people died and more than 10,000 people moved to safer places over the weekend after the Godavari, which begins in the state, crossed the danger mark in several places.
The weather office predicted more rains in Maharashtra over the next 12 hours.
Heavy monsoon rains, which sweep India from late May to September, also caused flooding in large parts of the Maharashtra state capital Mumbai, bringing rail and road traffic to a halt in the country's financial centre.
The latest deaths brought the nationwide toll since the start of monsoon season in mid-May to 432.