* Platts iron ore index at 9-month top
* Rally may stall, forward swaps drop
* China Dec, 2010 crude steel output up
* BHP Q4 iron ore output at record (Adds comments, China data, BHP output, swaps)
By Manolo Serapio Jr
SINGAPORE, Jan 20 (Reuters) - A key iron ore price index rose to its highest since April 2010 and offers in Asia rose 1 percent on Thursday on pre-Lunar New Year buying by Chinese steelmakers and fewer available cargoes.
"The iron ore bull keeps running. There's no sign of things winding down for Chinese New Year holidays," the Steel Index said in a note.
Spot prices are closing in on $200 a tonne, a record level last seen in February 2008, and traders say prices may hit that level if supply from major exporters India and Brazil remains hampered by logistical problems and bad weather.
Indian ore with 63.5 percent iron content was quoted in China at $188-$190 a tonne, including freight, on Thursday, versus $186-$188 on Wednesday, Chinese industry consultant Mysteel said.
The Platts 62 percent iron ore index IODBZ00-PLT rose $1 to $186 a tonne on Wednesday, matching the record level posted in April 20, 2010 which was its highest since Platts began publishing daily reference prices in June 2008.
Global miners including Brazil's Vale , the world's biggest iron ore producer, use the Platts index to decide prices for quarterly contracts which analysts say are likely to rise again in the second quarter after an estimated 7-8 percent hike in January-March.
BHP Billiton , the world's No. 3 iron ore producer, said its quarterly iron ore output rose 4 percent to a record level to meet swelling demand from its main customers in China and other parts of Asia.
Iron ore prices have rallied since 2011 started as Chinese steelmakers replenish stocks of the steelmaking ingredient after state-imposed production curbs in the latter part of 2010.
Despite the curbs, crude steel output by China, the world's biggest producer and consumer, rose 9.3 percent to a record 626.7 million tonnes in 2010, data showed on Thursday.
December output rose 6.3 percent in December from a year ago to 51.5 million tonnes and analysts say production in January is very likely to exceed last month's as Chinese steel mills boost profit margins amid rising steel prices.
Other iron ore indexes also hit fresh nine-month highs on Wednesday, with the Steel Index rising $1.30 to $182.70 a tonne, near the record $184.80 touched last April.
But some analysts say the rally may be showing signs of fatigue and could falter when the Chinese market is shut for the week-long Lunar New Year in early February.
"I think that we're nearing a top around about now," said Michael Gaylard, strategy director at Freight Investor Services in Shanghai.
"Chinese buyers will be pausing for breath around here and I think the Spring Festival holiday will put the screws on the rise. The pressure to take on cargo will relax for a little bit."
Prices of Singapore Exchange-cleared forward swaps <0#SGXIOS:> eased on Wednesday, with the February contract at below $181 a tonne and March down 84 cents to $177.33.
Whether the rally will have legs will hinge on the supply situation particularly from India, said Gaylard.
Iron ore exports from India, the world's third-biggest supplier, had been tight since its Karnataka state banned shipments in July. India's top iron ore producer, Orissa, is also looking at halting exports to meet domestic demand.
"If India curbs exports further, then this rally has potential to run a long way," he said. (Reporting by Manolo Serapio Jr.; Editing by Ed Lane)