SOFTS-Liffe cocoa dips to 10-month low, sugar firm

* West Africa cocoa mid-crops could be record size

* Record net shorts in ICE sugar, coffee

(Adds quotes, updates prices)

LONDON, Feb 18 (Reuters) - Liffe cocoa futures eased to a ten-month low on Monday as good supply prospects, combined with pent-up origin forward sales, kept the market on the defensive.

White sugar futures were firm, with ample supplies limiting price upside potential, while robusta coffee was little changed in subdued trading.

U.S. ICE agricultural markets were shut for the Presidents' Day holiday.

May cocoa on Liffe eased 6 pounds or 0.4 percent to 1,412 pounds a tonne at 1546 GMT, after earlier falling to 1,409 pounds, the lowest level since April 2012.

Cocoa dealers said West Africa's mid crop development had benefited from mostly favourable weather, although dry conditions were being monitored.

"Record mid crops are a distinct possibility but it has been a bit dry recently so we won't know until the second half of March," said a European analyst.

The dry season, which typically runs from mid-November through March, got off to a late start this season. However, strong seasonal Harmattan desert winds, high temperatures and almost no measurable rainfall over the past two months have dried soil.

Cocoa arrivals at ports in top grower Ivory Coast reached around 904,000 tonnes by Feb. 17 since the start of the season in October, exporters estimated on Monday, compared with 937,000 tonnes in the same period of the previous season.

SUGAR FIRM

May white sugar futures on Liffe traded up $7.60 or 1.6 percent at $497.90 a tonne.

"With New York closed today, we don't expect much out of the London market," said Nick Penney of brokerage Sucden Financial.

Penney added that it will be interesting to see how values in New York react when markets re-open Tuesday, after the latest Commitment of Traders report showed an increase in the raw sugar speculative short position.

Speculators raised their net short positions in raw sugar and coffee contracts on ICE Futures U.S. to record highs in the week to Feb. 12, increasing their bearish stance in markets abundant in supplies, U.S. Commodity Futures Trading Commission (CFTC) data showed on Friday.

Dealers said the large short positions made sugar and arabica coffee vulnerable to short covering rallies.

An expected third consecutive global sugar surplus has kept sugar markets under pressure thus far this year with ICE raw sugar futures falling to a two-and-a-half year low last week.

Robusta coffee futures were little changed, as dealers anticipated activity on the physical market would pick up this week, with business resuming Monday following the Lunar New Year holiday in top producer Vietnam.

"Demand growth for robusta is higher than for arabica," said a London-based broker, adding that the global balance sheet for robusta was expected to be quite tight in 2012/13, with supply close to matching demand.

Vietnam's customs department said the country exported nearly 219,000 tonnes (3.65 million 60-kg bags) of beans last month, a surge of nearly 86 percent from a year ago, exceeding initial estimates by traders and the government.

The latest export data pointed to another bumper crop following record supply from Vietnam in 2011/12.

"If you look at the shipment numbers from Vietnam I think there's more coffee around than some people have said there is," added the broker.

May robusta coffee futures on Liffe edged down $1, or 0.05 percent, to $2,056 per tonne.

"The reason you've got such strong demand for robusta is because it's cheap relative to arabica," said a European analyst.

Speculators increased a net long position in robusta coffee futures and options on NYSE Liffe in the week to Feb. 12, exchange data showed on Monday.

(Additional reporting by David Brough; Editing by Alison Birrane)