In Fujian province, floods killed 22 people, destroyed 19,000 homes and forced the evacuation of more than 50,000 residents, the China Daily said on Monday.
Landslides killed seven people in neighbouring Guangdong's Meizhou city, with heavy rains destroying 784 homes and damaging 15,000 hectares of farmland.
Weather forecasts predicted more heavy rains would pound southern China over the next 10 days.
"Heavy rains from 50-150 millimetres will sweep over central, south and southwest China," the People's Daily newspaper quoted a weather bureau official as saying, adding that it may reach more than 200mm in a few areas.
The official Xinhua news agency reported last week that up to the end of May, floods this year had killed 59 and affected 19 million people nationwide.
More than 71,000 houses had been destroyed and direct economic losses were estimated at 13 billion yuan ($1.62 billion).
South China is regularly plagued by heavy rains and floods at this time of year.