A power-plant equipment contractor that worked for the Venezuelan government seeks $300 million in damages from a Venezuelan bank, its chairman and another director for allegedly spreading knowingly false and defamatory information about it on the Internet.

In a lawsuit filed in Miami-Dade Circuit Court, Derwick Associates Corp. and co-founders Leopoldo Betancourt Lopez and Pedro Trebbau Lopez allege they have suffered severe damage from the actions of Venezolano de Credito SA Banco Universal, a Caracas-based bank with business ties to Miami; its president and chairman, Oscar Garcia Mendoza; and board member Rafael Alfonzo Hernandez.

The Barbados-based contractor’s suit calls Garcia the “mastermind” of a campaign that includes “false and malicious accusations” of money laundering, fraud, extortion, theft of hundreds of millions of dollars and partnering with corrupt politicians to profit from “illicit businesses.”

“We take this action now to bring an end to this malicious campaign of utterly false rumors aimed at destroying the impeccable reputation we have built through many years of hard work,” Betancourt said in a statement.

The lawsuit does not detail any connection between Derwick and the bank and offers no explanation for the purported animus.

The suit filed by Maria Ruiz of the Miami office of Kasowitz, Benson, Torres & Friedman and Hector Torres, Brian Kaplan and David Holahan of the firm’s New York office said Banco Venezolano maintained an office on Miami’s Brickell Avenue from 2001 to 2006 and operated a subsidiary, Venecredit, that still uses the Brickell address. A spokesman said the attorney would have no comment on the lawsuit.

Garcia serves as a director of Miami-based Novopayment Inc. and Plantation, Fla.-based Camp Claro Investments Inc., the suit said. Alfonzo serves as a manager of Boca Raton, Fla.-based Alfistais LLC and owns property in Pompano Beach, Fla.

The complaint filed September 13 and assigned to Circuit Judge Diane Ward said Garcia and Alfonzo’s campaign “began as isolated attacks on Facebook, Twitter and email but rapidly escalated to a highly organized and aggressive conspiracy and campaign to defame plaintiffs and anyone associated with Derwick.”

The lawsuit said an article containing “numerous false and defamatory statements concerning plaintiffs” appeared August 2 on a website controlled by Garcia and Alfonzo. The suit lists 16 statements about the plaintiffs, including that they “launder the money originating from oil and electricity corruption and join illegal financial deals,” are “part of a ‘criminal group’ that have amassed a ‘pot … [of] up to about two billion dollars … through which [they] launder money by making investments’” and “at the present time [plaintiffs] are out of the country [Venezuela] as it seems that they are being investigated by the intelligence agencies.”

The court file does not list lawyers for Banco Venezolano.

Betancourt and Trebbau, both residents of Venezuela, founded Derwick in 2007, the complaint said. Before that Betancourt, a graduate of Suffolk University in Boston, was director of a Venezuela-based affiliate of Japanese manufacturer Kawasaki Heavy Industries Ltd., the suit said. Trebbau, a Boston College graduate, was a project manager for Procter & Gamble de Venezuela.

Along with their offices in Caracas, the two incorporated Derwick Associates USA LLC in late 2010 with an office at Fort Lauderdale-Hollywood International Airport, state records show. The corporate registration was dissolved September 28 for lack of an annual report.

The suit alleges defamation of Derwick, Betancourt and Trebbau; tortious interference with contract and with business relationships; deceptive and unfair trade practices; and civil conspiracy. The company is seeking preliminary and permanent injunctions as well as monetary damages.

Derwick won 12 bids to build power plants during a 2009-2010 energy crisis in Venezuela capped by the Hugo Chavez-led government’s declaration in February 2010 of an “energy emergency,” the complaint said.

Chavez celebrated winning his third term as president Sunday, vowing Venezuela will continue on its path of Bolivarian socialism. The government took over the nation’s electricity sector after his 2006 victory.