Hyundai Motor Co., South Korea's top automaker, on Wednesday dismissed a media report that it has agreed to settle a class-action lawsuit by U.S. consumers who say they were misled by the carmaker's inflated fuel economy ratings.

Hyundai said it has produced no specific progress in resolving the legal trouble stemming from its incorrect fuel economy rating for about 900,000 cars sold in the United States between 2010 and 2012.

"No agreement has been made," a Hyundai official said. He said it remains to be seen whether his company will reach a class-action settlement, citing legal procedures are under way.

Another Hyundai official also sounded a note of caution, saying it is difficult to say whether his company will hold negotiations with lawyers who represent the plaintiffs to settle the suit. The two Hyundai officials asked not to be identified, citing policy.

Their comments came hours after Bloomberg News reported from Los Angeles that "Hyundai agreed in principle on terms of a settlement," citing a filing in federal court in L.A by lawyers for the plaintiffs.

In November, Hyundai and its sister carmaker Kia Motors Corp. said procedural errors at testing operations were to blame for inaccurate fuel economy ratings for the cars sold in the U.S.

Hyundai and Kia, which are flagships of Hyundai Motor Group, the world's fifth largest carmaker, have said the average fuel economy ratings for their 13 U.S. models were unintentionally but incorrectly listed as 27 miles per gallon (mpg), up 3 percent from the actual 26 mpg.

The U.S. government has announced plans to require automakers to achieve average fuel economy ratings of 34.1 mpg and reach 250 grams per mile in carbon dioxide emissions by 2016.

The rare admission has prompted the South Korean government to intensify its checks on fuel efficiency of new vehicles to narrow a currently wide gap between the fuel efficiency claimed by automakers and their actual efficiency.

South Korea plans to reduce fuel efficiency ratings' margin of error to plus or minus 3 percent, from the current 5 percent. The measure is expected to take effect later this year. (Yonhap News)