Analysts and mines experts had predicted prices of iron ore, Australia's most lucrative export commodity, could fall as low as $140 per tonne in the coming months.

In September, spot iron ore prices grew above $181 per tonne, but on Monday fell deeply to $157.25.

The analysts and mines experts said the commodity's weakening prices could extend in the in the early part of this quarter.

Fortescue Metals Group marketing spokesman David Liu told The Sydney Morning Herald it's the Chinese monetary policy that is affecting demand for the main steel-making ingredient.

''In China, steel prices have been under pressure recently, the government's monetary supply restrictions to rein in inflation have impacted on steel mills and their downstream processes in particular,'' he said.

"The fourth quarter will be much more difficult than what was expected in terms of prices in China," Marco Saravalle, an equity analyst at Coinvalores Corretora de Valores, told Bloomberg. "There's a formula. But there is no way to escape spot prices for very long."

On Monday, reports came out that Brazil's Vale offered its Chinese customers to purchase the iron ore raw material for fourth-quarter contracts at a much cheaper rate, in what seems to be an indication that iron ore miners were giving in to Chinese pressure.

Reports said iron ore miners were selling to Chinese steel mills at $175 a tonne. But Chinese mills were not buying since the trading parameter used for the fourth-quarter contract ratewas based on June-August average spot prices. Iron's ore's current rate is less than $160 a tonne average.

But iron ore miners allayed prices will likely rebound coming into the new year, as they expect Chinese steel consumption to rise 7.5 per cent this year.

''We are not deterred by some of the short-term softening in the market,'' Fortescue Metals Group chief executive Neville Power told The Sydney Morning Herald. ''Most of that appears to be a carry-over from the financial uncertainty in Europe and I think once that is sorted out we will see most of the volatility and cautiousness in the Asian markets disappear.''

Other iron ore global players, such as Rio Tinto and Vale, believed bulk-buying for the raw commodity will continue to hold up and that demand remains strong because of advancements in the Chinese economy and infrastructure outlays.

China, the world's biggest buyer of iron ore, revealed last Thursday it had imported just over 60 million tonnes of iron ore in September, the second highest on record.

Iron ore sales is forecast to contribute $A65.3 billion to the nation's coffers this year.