* Arabicas sink to within sight of key level of $1 per lb

* Raw sugar recovers from one-month low on currency support

* Cocoa futures continue to ease as harvest pressures build

(New throughout, updates prices and market activity)

By Chris Prentice and Freya Berry

NEW YORK/LONDON, Nov 4 (Reuters) - ICE arabica coffee futures sank to their lowest level since March 2009, pressured by abundant global supplies and speculator selling, while robusta coffee in London edged down in mixed trading and hovered near Friday's price, the lowest in more than three years.

ICE raw sugar futures gained, recovering from a one-month low on currency and technical support.

Cocoa futures on ICE hit a four-week trough due to harvest pressure from West Africa, the world's top growing region.

December arabica coffee on ICE Futures U.S. KCc1 sank 1.85 cents, or 1.8 percent, to settle at $1.0370 per lb, just above the day's 4-1/2 year low of $1.0335.

It was the spot contract's biggest one-day decline since mid-September as a net short position held by speculators and excess supplies kept weighing on the depressed coffee market.

Losses picked up at the end of the session, as technical weakness drove even more selling, leaving the spot contract at its lowest close since December 2008.

"The funds continue to be short, and the market continues to go lower," said Sterling Smith, a futures specialist with Citigroup in Chicago.

Market open interest has climbed as prices have set lows, which market watchers view as evidence of new selling.

Total open interest reached 171,087 lots on Friday, up from 170,274 lots previously, and the highest level since June, the most recent ICE data showed.

Recent rains are aiding flowering in Brazil, signaling the potential for another year of huge output in the top grower next season.

Traders said $1 per lb as a key area of psychological support that may prompt roasters to buy or speculators to cover short positions, though potential short-covering rallies were expected be short-lived.

"We know that if there is a short-covering rally in New York then Brazil (producers) will be there to cap the market," said a European broker.

Liffe January robusta coffee futures LRCc2 eased $6, or 0.4 percent, to finished at $1,483 a tonne.

The second month remained near Friday's more than three-year low of $1,453 set under pressure from a huge harvest in Vietnam.

Weather concerns and depleting exchange stocks prompted light short-covering and buoyed robusta futures from further losses on the day.

"For the robusta market the situation is not that bleak because there has been a significant run-down in stocks, and I think sooner or later the market will react to this," Stefan Uhlenbrock, analyst with F.O. Licht, said.

RAW SUGAR RECOVERS FROM ONE-MONTH LOW

ICE March raw sugar futures SBc1 firmed, finishing up 0.07 cent, or 0.4 percent, at 18.32 cents a lb.

Prices got a boost early in the session as Brazil's real currency strengthened. Support at the contract's 50-day moving average of 18.13 also lifted prices off a one-month low of 18.17 cents a lb.

Exporters this year have boosted sales of dollar-traded commodities to capture the gains in the U.S. dollar against the sinking Brazilian real BRBY .

Even so, the lack of buying by end users continued to weigh and kept prices rangebound.

The contract SBc1 is down some 9 percent from a one-year high of 20.16 cents set on Oct. 18 as a fire ravaged a Copersucar-controlled terminal in Santos, Brazil.

Dealers said speculators have since begun to dial back a huge net long position in raw sugar futures and options.

The noncommercial dealers switched from a bearish stance to a huge bullish one and drove prices up from July's three-year low below 16 cents a lb.

"People are looking at a lack of demand right now and what it means. Now we're coming back down to find out where the demand is," said Michael McDougall, a senior vice-president at Newedge USA.

December white sugar on Liffe LSUc1 gained $4.30, or 0.9 percent, to finish at $485.60 a tonne.

The second month's discount LSUc2 to the front month

LSUc1 faded to near even from $4.40 per tonne previously in gyrations ahead of the December contract's expiry on Nov. 15.

Dealers attributed the big move to rolling forward of short positions.

ICE December cocoa CCc1 finished up $3, or 0.1 percent, at $2,654 a tonne after hitting a one-month low of $2,630.

Prices saw "a touch of commercial buying on skittish volume" at the fresh lows, said Citigroup's Smith.

Concerns about dry weather and supply deficits drove speculators to pile into the cocoa market and lift prices to a more than two-year high of $2,780 on Oct. 22.

Building harvest pressure and available supplies in West Africa, the world's top growing region, have since slowed that momentum.

"The weather situation has improved, cocoa butter prices have backed off," said Smith.

Cocoa purchases declared to Ghana's industry regulator reached nearly 108,000 tonnes by Oct. 24, more than 20 percent higher than in the previous year. ID:nL5N0IP26F

London March cocoa futures LCCH4 fell 6 pounds, or 0.4 percent, to finish at 1,696 pounds per tonne.

(Additional reporting by David Brough in London; Editing by David Gregorio)

((christine.prentice@thomsonreuters.com)(+1)(646)(223 6136)(Reuters Messaging: christine.prentice.thomsonreuters@reuters.net))

Keywords: MARKETS SOFTS/