The company, Bonita Springs, Florida-based Paice LLC, claims that popular Toyota hybrids like the third-generation Prius and the Lexus HS250h contain technology that violate its patents related to the propulsion of gas-electric vehicles.

Paice is seeking to bar the import of the vehicles into the U.S. The U.S. International Trade Commission, which investigates claims of trade violations, voted to launch the probe on Monday.

After the ITC decides to begin an investigation, a judge is named usually within 45 days and hearings are held, an ITC spokeswoman said. If the ITC sides with Paice, the trade body could issue penalties including a possible ban on the hybrids' import.

A Toyota representative was not immediately available to comment Tuesday. The Japanese automaker issued a statement last month when Paice first complained to the ITC saying it "has many patents on the hybrid technology and believes that it has strong defences against all of Paice's claims and that it will prevail in the ITC proceeding."

American Depositary Shares of the company added $2.23, or 2.9 per cent, to $77.26 in afternoon trading.