QUEENSLAND'S beleaguered sugarcane farmers faced an 18 per cent fall in international prices, the nation's chief commodities forecaster warned yesterday.

The Australian Bureau of Agricultural and Resource Economics said the world economic slowdown and oversupply from the world's biggest sugar producer, Brazil, would force down prices. Cane farmers have suffered in recent years from bad weather and an onset of the disease orange rust in the local crop.

ABARE is also tipping falls in wool and cotton prices as the economic slowdown eats into world demand.

But overall, the commodities forecaster said Australian farmers and miners should enjoy another good year on the back of the low dollar.

Australia is set to reap $90.5 billion from its commodity exports this financial year, with the farm sector enjoying the biggest boost.

Rural exports will jump to $30.9 billion, from $29.4 billion last year, more than making up for falls in earnings from the minerals sector.

Mining exports are expected to drop to $55.6 billion from $56.4 billion, while the energy sector will drop $900 million to $25.7 billion.

ABARE's executive director, Brian Fisher, said the fall in the dollar was more than making up for declining demand caused by the global economic slowdown.

"A relatively weak Australian exchange rate, especially against the US dollar, is expected to largely offset the adverse effects on earnings of lower commodity prices on world markets," he said.

The economic slowdown is expected to eat into the strong gains made by the minerals and energy sector, although again the low dollar should keep profits up.

Coal production is expected to climb 3 per cent, and higher world prices should boost its export value 22.8 per cent to $13.2 billion.

Apart from coal, exports of gold, iron ore, lead and manganese are expected to climb this financial year.

The value of crude oil exports, which skyrocketed last year on the back of high prices, is expected to drop 30.3 per cent, while the value of natural gas and LPG exports is also tipped to fall.

One of the biggest rural success stories is expected to be the dairy sector, which should enjoy a 7 percent improvement in prices while total exports will climb 20 per cent to $3.6 billion.