RIO DE JANEIRO (Reuters) - Floods and landslides devastated towns in a mountainous area near Rio de Janeiro, killing dozens of people and bringing the death toll on Wednesday from days of heavy rain in southern Brazil to at least 83. At least 54 people were killed in Teresopolis about 100 km north of Rio, the towns mayor said, after hillsides and riverbanks buckled under the equivalent of a months rainfall in 24 hours. At least 16 other people were killed in two other towns in the region, officials with the governments Civil Defence agency said. The rains sweeping southeastern Brazil also killed 13 people in Sao Paulo state on Tuesday and snarled transport in the countrys financial capital. The death toll was expected to rise, with about 50 people believed missing just in Teresopolis, mayor Jorge Mario told Globo television. There are 48 dead, and that number will rise because rescue teams are still arriving in the areas that have been worst affected, he said, adding that about 1,000 people had been left homeless. Its the biggest catastrophe in the history of the town. Thousands of people in the picturesque area, known as the Serrana region, were isolated by the flood waters and cut off from power and telephone contact. Meanwhile, heavy monsoon rains on Wednesday kept Sri Lankas president from visiting areas inundated by flooding that has killed 18 people, forced 196,000 from their homes across a third of the nation, and threatened food supply. Nearly a fifth of Sri Lankas rice paddies are either destroyed or under standing water that could wipe out the crop, the Agriculture Ministry said, raising concerns over supply shocks and higher food inflation for Sri Lankas staple food. Greater-than-normal monsoon rains since early January have hit the Indian Ocean island in the Northern, Eastern, Central and North Central provinces, building up to cause mudslides, swamp roads and burst hundreds of dams and reservoirs. Sri Lankas Disaster Management Centre said that at least 18 people had been killed across the country, with a landslide in the hilly Kandy area killing at least seven people. Meanwhile, at least 30 people may have been killed and about 1,000 homes damaged by floods in South Africa in the past week, a government estimate showed on Wednesday. There were no estimates available yet for the amount of damage caused in the major African food producer and global mining power, the ministry of cooperative governance said in a statement. The worst affected areas (are) the metropolitan areas of Johannesburg and Pretoria, where an estimated 12 people have lost their lives so far, it said. Meanwhile, massive floods shut down the centre of Australias third-largest city, sent thousands fleeing from their homes and sparked panic buying of food on Wednesday as rescuers searched for 43 people missing in floodwaters. Australias biggest floods in a century have so far killed 16 people since starting their onslaught across northern mining state Queensland last month, crippling the coking coal industry, destroying infrastructure, putting a brake on the economy and sending the local currency to four-week lows. The flood surge is expected to peak in Brisbane, a riverside city of two million people, before sunrise on Thursday and last for days. We are in the grip of a very serious natural disaster, Queensland state premier Anna Bligh said, predicting almost 20,000 homes could be flooded at the rivers peak. Brisbane will go to sleep tonight and wake up to scenes many will never have seen before in their lives, she warned. Brisbane residents on Wednesday pushed food-laden shopping carts through submerged streets, others waded in shoulder-high water to rescue possessions, while boats and pontoons were ripped from moorings in the Brisbane River and smashed into bridges as the muddy brown tide gathered strength. At flooded intersections people paddled surfboards through floodwaters, balancing their possessions on the deck of the boards, while boats ferried evacuees to dry ground. I am feeling a sense of horror and awe at the power of the river. Sadly in coming hours we will see bits of peoples homes float down the river, Brisbane Mayor Campbell Newman said, warning the torrent could take three to four days to subside. Four thousand people sheltered in evacuation centres.