* Shanghai rebar climbs as much as 1.2 pct
* Expectations of seasonal steel demand from September
By Manolo Serapio Jr
MANILA, Aug 11 (Reuters) - Iron ore futures in China jumped as much as 3.8 percent to their highest in more than a month on Tuesday, propped up by hopes that steel demand in the world's top consumer would pick up next month.
Shanghai rebar steel futures rose over 1 percent to recover from a two-week low. Construction activity in China usually resumes in September after the summer lull, potentially boosting steel consumption which has been shrinking this year.
"Steel demand in September and October is highly likely to be better than in August and prices may not drop significantly," said Wang Li, a consultant at CRU Group in Beijing.
Efforts by Beijing to increase investment in infrastructure may also be felt in the latter part of the third quarter, said Wang.
Iron ore for January delivery on the Dalian Commodity Exchange climbed as far as 383 yuan ($61) a tonne, its highest since July 6. It was up 2.6 percent at 378.50 yuan by midday.
The January rebar contract on the Shanghai Futures Exchange SRBcv1 was last up 0.6 percent at 2,062 yuan a tonne after rising as much as 1.2 percent.
Weak demand at home has fueled a sharp rise in China's steel exports, with shipments of 9.73 million tonnes in July, up 21 percent from a year ago and near the record high of 10.29 million tonnes posted in January.
"We currently forecast China's crude steel output to contract 2 percent this year as weaker domestic consumption offsets stronger steel export growth," Commonwealth Bank of Australia said in a note.
"If China's steel product export growth expands faster this year, we could see China's steel output lift, implying a stronger iron ore price."
Firmer futures bode well for the price of spot iron ore which rose to a one-month high of $56.40 a tonne last week, recovering from July lows when it sank to its weakest in a decade.
Iron ore for immediate delivery to China's Tianjin port last stood at $56.30 a tonne on Thursday, according to The Steel Index (TSI). TSI did not publish prices on Friday and Monday due to the public holidays in Singapore. Pricing will resume later on Tuesday.
($1 = 6.2986 Chinese yuan)