* Shanghai rebar steady below three-year high
* Lack of high-grade iron ore at Chinese ports - CBA
By Manolo Serapio Jr
MANILA, Feb 23 (Reuters) - Iron ore futures in China ticked down on Thursday, sliding further from a record high reached on Tuesday, amid doubts on the strength of the rally in the steelmaking raw material given plentiful stocks at Chinese ports.
Inventories of imported iron ore at major Chinese ports reached 127.55 million tonnes as of Feb. 17, the highest since at least 2004, according to data tracked by SteelHome consultancy. SH-TOT-IRONINV
"The rally to the highest level since 2014 has occurred at the same time as stocks have been rising, which has caused some producers to question the sustainability of the rise," ANZ analysts said in a note.
The analysts were referring to the surge in the price of spot iron ore .IO62-CNO=MB to $94.86 a tonne on Tuesday, the strongest since August 2014, based on data from Metal Bulletin.
The spot benchmark dropped 0.6 percent to $94.30 on Wednesday.
The rally in spot iron ore followed the upturn in Chinese futures this week, with the most-traded contract on the Dalian Commodity Exchange DCIOcv1 hitting a record high of 741.50 yuan ($107.79) on Tuesday.
Dalian iron ore has since retreated, trading at 721.50 yuan a tonne by 0253 GMT on Thursday, down 0.3 percent.
Iron ore has tracked the rally in Chinese steel prices as traders built inventories hoping Beijing's plans to boost infrastructure spending this year would boost steel demand.
The price gains in the raw material also reflected strong appetite for higher grade iron ore as Chinese steel mills lift productivity.
"We believe that iron ore prices may hold up in coming weeks due to an absence of medium to high grade ore at Chinese ports and as seasonal factors weigh on seaborne trade," Commonwealth Bank of Australia analyst Vivek Dhar said in a note.
"Growing surplus risks in China's steel market should eventually weigh on iron ore prices as restocking demand eases."
The most-active steel rebar future on the Shanghai Futures Exchange SRBcv1 was steady at 3,546 yuan per tonne. The construction steel product hit a three-year high of 3,630 yuan on Tuesday.
Inventories of rebar in China reached 8.397 million tonnes on Feb. 17, the most since April 2014, according to SteelHome. SH-TOT-RBARINV
($1 = 6.8790 Chinese yuan)