Iron ore dropped to near its weakest level since 2009 and looks poised for further losses as a supply glut kept the pressure on the commodity that has fallen 42 percent this year.

A looming winter in China which in past years has increased steel mills' appetite for imported iron ore with most domestic mines shut is unlikely to provide a fresh boost to prices, traders said.

"Many mills have already shifted to using more imported iron ore because of the slump in prices this year so I don't see that the additional demand during winter will be much higher," said a Shanghai-based iron ore trader.

The slump in prices has forced many high-cost iron ore mines in China, the world's top iron ore importer and consumer, to close down as top producers from Australia and Brazil boost production to record levels to ship more to China.

Australian shipments of iron ore to China from Port Hedland, which handles about a fifth of the world's seaborne trade, rose 6.5 percent to a near record 31.71 million tonnes in October, port data showed.

Iron ore for immediate delivery to China .IO62-CNI=SI fell 0.9 percent to $77.80 a tonne on Monday, according to data compiled by The Steel Index.

That was just a tad above this year's trough of $77.50 reached at the end of September and was the lowest point for iron ore since 2009.

Iron ore futures edged lower on Tuesday, with the most-traded May contract on the Dalian Commodity Exchange down 1.3 percent at 520 yuan ($85) a tonne by midday.

The January contract on the Singapore Exchange slipped 0.7 percent to $76.31 a tonne.

"Demand remains weak as Chinese buyers sit on the sidelines with many steel mills forced to halt production leading up to the APEC meeting," ANZ Bank analysts said in a note.

Dozens of steel mills in industrial areas straddling the capital Beijing have shut from Nov. 1 to cut smog before leaders, including U.S. President Barack Obama, attend the Nov. 5-11 Asia-Pacific Economic Cooperation meeting.

China imposed similar shutdowns on industry during the 2008 Beijing Olympics.

Bulk of the shutdowns were in Hebei which accounts for around 30 percent of China's total steel capacity. But Cao Bo, analyst at Jinrui Futures in Shenzhen, estimates that only about 7 percent of the province's output will be shut down during the APEC meeting.

"That means only about 3 percent of China's total production will shut down. The effect on output is very, very small," said Cao.

The most-active rebar for May delivery on the Shanghai Futures Exchange eased 0.2 percent to 2,556 yuan a tonne, off a session low of 2,529 yuan.