UPDATE 1-Iron ore slumps as Australia's shipments seen higher in October

* Dalian iron ore drops as much as 2.5%

* Singapore iron ore hits one-week low

* Dalian coke futures rise for fifth day (Updates prices, adds graphic)

MANILA, Nov 5 (Reuters) - Dalian and Singapore iron ore futures fell on Thursday as exports of the steelmaking ingredient by top producer Australia likely picked up last month that may push China’s portside inventories higher.

About two-thirds of Australia’s iron ore exports is shipped to China, the world’s top steel producer, and the commodity has been spared so far from the simmering tensions between Beijing and Canberra.

Iron ore on China’s Dalian Commodity Exchange ended daytime trading down 1.1% at 783 yuan ($117.82) a tonne, after falling as much as 2.5% earlier in the session.

The Singapore Exchange’s iron ore benchmark slipped 0.2% to $112.84 a tonne at 0705 GMT.

Australia’s iron ore exports in October were projected to have increased to 78 million tonnes in October, from the prior month’s 74 million tonnes, based on Westpac’s estimate.

Australia’s exports in the third quarter were generally lower than might have been expected due to maintenance activity by major miners, said Robert Rennie, head of Westpac’s financial market strategy.

“The good news is that the impact of maintenance appears to be waning,” he said, citing an 18% year-on-year rise in export volumes at Port Dampier and Cape Lambert last month.

Coupled with increased iron ore shipments from Brazil, the steady supply from Australia pushed port stockpiles in China last week to the highest since mid-February, SteelHome consultancy data showed. SH-TOT-IRONINV

Spot prices, however, have been generally stable this week, trading at $118.50 a tonne on Wednesday, based on SteelHome data. SH-CCN-IRNOR62

Winter steel production cuts and rising iron ore inventories are likely to prompt steel mills to go slow on purchases, analysts said.

Construction steel rebar on the Shanghai Futures Exchange gained 0.3%, while hot-rolled coil climbed 0.5%. Stainless steel slipped 0.5%.

Dalian coking coal dropped 1.6%, but coke rose for a fifth day by 0.8%.

Reporting by Enrico Dela Cruz, Editing by Sherry Jacob-Phillips