* Argentine suit stems from $19 bln ruling against Chevron * Chevron says pollution judgment fraudulent, unenforceable * Two-decade legal dispute has spread to several countries By Guido Nejamkis BUENOS AIRES, Jan 30 (Reuters) - An Argentine appeals court has upheld a freeze on up to $19 billion worth of assets held by U.S. oil major Chevron Corp in Argentina as part of an environmental lawsuit by Ecuadorean villagers, one of the plaintiffs' lawyers said on Wednesday. An Ecuadorean court last year ordered Chevron to pay the enormous sum for contamination of watersheds over nearly 30 years that the plaintiffs say sickened indigenous tribes people and farmers in the Ecuadorean Amazon. Chevron, which vowed to fight the latest ruling, has refused to make any payments and accuses Ecuadorean courts of fraud. Because the company has few assets in Ecuador, the plaintiffs are seeking enforcement of the ruling in other nations including Argentina, Brazil and Canada. The two Chevron subsidiaries targeted by the freeze, Chevron Argentina and Ing. Norberto Priu, asked the court in November to lift the asset freeze on the grounds that they were not directly owned by Chevron. The court rejected their appeal unanimously, lawyer Enrique Bruchou said. "We are very pleased with the resolution of the Court of Appeals, which is well founded," Bruchou said in a statement sent to Reuters. California-based Chevron said it would "pursue all available legal remedies to reverse the interim measure." "Chevron's view of the situation remains unchanged; the precautionary embargo is unfounded and based on a judicial fraud in Ecuador. If the plaintiffs' lawyers believed they had a legitimate judgment they would seek to enforce it in the United States, where Chevron Corporation resides," a company spokesman said in an emailed comment. The plaintiffs' lawyers estimate that Chevron's assets in Argentina are worth about $2 billion and that they could obtain some $600 million a year if the ruling were enforced. Chevron argues that the company has no direct assets in Argentina because its operations in the country are conducted by subsidiaries. Chevron signed an accord with state-controlled YPF, Argentina's No. 1 energy company, in December that aims to pave the way for major investment in the country's shale oil resources. Bruchou said Chevron should acknowledge the potential liability in company financial reports. It is due to report fourth-quarter earnings on Friday. "In the immediacy of Chevron submitting its fully audited 2012 financial statements, we hope this will help the company, and in particular its Audit Committee and its auditors, focus on the need of recognizing and accruing the loss contingency in their 2012 financial statements, in compliance with clear guidelines of the SEC rules," he said. "According to such rules, if a loss is 'probable' and the amount of loss can be 'reasonably estimated' the company must recognize and accrue it in its financial statements."