(Reuters) - The U.S. Commodity Futures Trading Commission (CFTC) is planning to issue a report next month that suggests that wild swings in oil prices were significantly driven by speculators, the Wall Street Journal reported on its website on Tuesday.

A 2008 report by the main U.S. futures-market regulator that attributed oil-price swings primarily on supply and demand was based on "deeply flawed data," Bart Chilton, one of four CFTC commissioners, told the paper in an interview on Monday.

The CFTC did not reveal preliminary figures from the report to the paper and declined to discuss the previous data.

Reuters attempts to contact the agency outside regular U.S. business hours were unsuccessful.

The CFTC will hold the first of three hearings on Tuesday to consider whether to limit holdings of energy and agricultural contracts and whether some traders should be allowed to exceed so-called position limits.

(Reporting by Ajay Kamalakaran in Bangalore)