* Copper prices seen at $4,890 average in 4Q - NAB
* LME on warrant tin stocks falling towards lowest since 2008
* Coming Up: U.S. Durable goods June at 1230 GMT
* Coming Up: FOMC releases policy statement at 1800 GMT (Adds detail; updates prices)
By Melanie Burton
MELBOURNE, July 27 (Reuters) - London copper dropped to near one-week lows on Wednesday as sentiment soured in China, and ahead of the outcome of the U.S. Federal Reserve meeting where it is expected to hold rates.
China stocks tumbled on fears of tighter regulatory restrictions after Beijing officials earlier this week warned about asset bubbles.
The Fed is expected to defer any possible increase until September or December, as policymakers hold out for more evidence of a pickup in inflation.
“My medium to longer term view on copper prices is fairly bearish but the recent increase in prices seems to be a general reflection of risk on, as people become more optimistic on looser policy for longer,” said Amy Li of National Australia Bank in Melbourne.
“How long will the rally last? Prices could go up further but at some stage, they will need to come down as a result of the supply glut and slowing Chinese demand.” NAB sees copper at $4,890 average in the fourth quarter.
Three-month copper on the London Metal Exchange eased 0.6 percent to $4,901.50 a tonne by 0745 GMT, erasing gains from the previous session. Prices had slipped to the lowest in a week at $4,859 a tonne on Tuesday.
Shanghai Futures Exchange copper fell 0.2 percent to 37,740 yuan ($5,659.61) a tonne.
Chilean copper miner Antofagasta said full-year copper production would be at the lower end of the 710,000 to 740,000 tonnes it predicted in January as a global market surplus shows little sign of easing.
In other metals, LME tin climbed by 0.3 percent to 17,725 a tonne, not far off 17-month highs tipped earlier this month at $18,255, while ShFE tin rallied 2.6 percent.
Supporting prices, LME stocks available for delivery, or on warrant, have fallen to just 3,465 tonnes, close to February lows near 3,200 tonnes, which were the least since late 2008.
In news, China’s top leaders pledged to keep economic growth steady in the second half of the year, while creating favourable conditions for supply-side reforms, state media reported.
Profits earned by China’s industrial firms rose 5.1 percent in June from a year earlier, quickening from May and suggesting a government spending spree is helping steady the economy.
Elsewhere, aluminium fell below $1,600 for the first time since late June this week, pressured lower by stock increases in LME warehouse in Asia and talk of more to come, broker Triland said in a note, adding lower oil prices also weighed.
“Support levels are being tested around $1,590/95, so a close below here could precipitate more follow-through selling.”
Three month LME copper
Most active ShFE copper
Three month LME aluminium
Most active ShFE aluminium
Three month LME zinc
Most active ShFE zinc
Three month LME lead
Most active ShFE lead
Three month LME nickel
Most active ShFE nickel
Three month LME tin
Most active ShFE tin
$1 = 6.6683 Chinese yuan Reporting by Melanie Burton; Editing by Richard Pullin and Subhranshu Sahu