Argentina's main grains port of Rosario was paralyzed at midday on Wednesday by an open-ended wage strike by boat captains needed to help dock incoming cargo ships, the country's port management chamber said. At a busy time of the year for exporters, smack in the middle of Southern Hemisphere soy and corn harvest season, the country's dock workers also threatened a work stoppage if their own pay demands are not met. The strikes threaten to slow supply from grains powerhouse Argentina, putting upward pressure on world food prices. The country is the world's top exporter of soymeal livestock feed, its No. 3 supplier of raw soybeans and a major producer of corn and wheat. The captains of small vessels that take river pilots out to meet incoming grains ships are demanding higher wages, Guillermo Wade, president of the Port and Maritime Activities Chamber, told Reuters. The pilots must board cargo ships in order to guide them to their berths in Rosario ports such as San Lorenzo. "There is no way to replace the service of the boats that take the pilots to the incoming cargo ships," Wade said. The union representing the boat captains says the strike will continue until its wage demands are met. Tough pay negotiations are common in Argentina, as workers negotiate wages in line with the country's double-digit inflation rate. Meanwhile, ships entering Rosario's port area are dropping anchor along the Parana River to wait out the work stoppage, Wade said. On top of the captains' strike, the powerful CGT labor federation announced that its dock and soy crushing workers would begin a 24-hour strike at midnight Wednesday, also over pay. "And if we do not reach a deal we will start another strike at midnight on Monday, for an indefinite period of time," Edgardo Quiroga, spokesman for the CGT told Reuters. The union is negotiating a pay package with CIARA-CEC, Argentina's chamber of grains exporting and soy crushing companies. The government said Argentina's inflation rate was 1.3 percent on the month in March. Many private analysts question the credibility of government data and estimate inflation in Latin America's No. 3 economy about 29 percent annually. (Reuters)