BRISBANE, Australia, Jan. 17 (UPI) -- Australia's flood crisis will likely be the most expensive natural disaster it has ever had, the country's treasurer said Monday.
"It looks like this is possibly going to be, in economic terms, the largest natural disaster in our history," Wayne Swan, who is also deputy prime minister, told the Australian Broadcasting Corp.
Rebuilding flooded areas -- including Brisbane, capital of the northeastern state of Queensland -- "will involve billions of dollars of commonwealth moneyand also state government money," and will likely take years, Swan said.
The massive cleanup in advance of the enormous rebuilding effort began during the weekend.
Since December, two-thirds of Queensland -- an area twice the size of Texas -- has been beset by flooding that has left more than 25 people dead and scores of others missing.
The unremitting floodwaters rolled southward into Victoria Monday and 3,500 people were evacuated in northern towns.
The floodwaters now threaten 1,400 homes in 43 other communities, the BBC reported.
More than 100 homes in Horsham, a town of 14,000 midway between Melbourne and Adelaide, were at least partly underwater late Monday despite some 45,000 sandbags laid by residents and State Emergency Service volunteers, Horsham Mayor Michael Ryan told the ABC.
The Wimmera River, which has flooded Horsham to historic proportions six other times since 1894, is expected to peak at 12.6 feet Tuesday, and its floodwaters will literally split the town in two, the emergency service said.
Flood victims complained about getting little warning before their homes were swamped.
In the past week, Victoria's emergency warning system has been activated more than 25 times, but some people told the (Melbourne) Herald Sun they got less than 30 minutes' notice.
Prime Minister Julia Gillard visited inundated Echuca in northern Victoria Monday.
Echuca, an Aboriginal name meaning "Meeting of the Waters," is situated at the junction of the Goulburn, Campaspe and Murray rivers.
In Brisbane, 19 homes and 74 businesses were still flooded Monday, The Courier Mail in Brisbane reported. High tides still threaten low-lying properties.
In Melbourne, the Australian Open, the first of the four annual Grand Slam tennis tournaments, began a day after tennis stars came together for two exhibition matches to raise money for flood victims.
The Rally for Relief at Rod Laver Arena featured Roger Federer, Rafael Nadal, Andy Murray, Caroline Wozniacki, Kim Clijsters and others.