SINGAPORE/PARIS: Chicago soybean futures fell on Tuesday, pulling further away from a 6-1/2 year high hit in the last session, as expectations of progress in Argentina's port labour talks weighed on prices.

Wheat was little changed after two consecutive sessions of declines, while corn dropped for the first time in 12 sessions.

"Soybeans have had a strong run-up in prices but there have been some recent rains in Brazil and Argentina, adding pressure on prices," said one Singapore-based trader.

"The market is watching the situation in Argentina as several shipments have been delayed."

The most-active soybean contract on the Chicago Board of Trade (CBOT) slid 0.4 to $12.51-3/4 bushel by 1130 GMT, heading for a second straight session of falls. The market had climbed to its highest since June 2014 on Monday at $12.80-1/2 a bushel.

Wheat was up 0.2% at $6.15-3/4 a bushel, while corn lost 0.2% to $4.55-1/2 a bushel.

A labour strike by oilseed workers and grain inspectors has idled Argentina's ports, backing up more than 140 export ships, though government-sponsored talks are scheduled for Tuesday to try and hammer out a 2021 compensation package.

The CIARA-CEC chamber of soy byproduct manufacturers will meet on Tuesday with the two main unions representing oilseed workers.

The SovEcon agriculture consultancy said on Monday that it had downgraded its estimate for Russia's 2020/21 wheat exports to 36.3 million tonnes from a previously expected 40.8 million tonnes due to an upcoming wheat export tax.

Large speculators raised their net long position in Chicago Board of Trade corn futures in the week to Dec. 21, regulatory data released on Monday showed.

Algeria's state grains agency OAIC has issued an international tender to buy milling wheat, which supported European wheat prices in late trade on Monday.