NEW YORK (Reuters) - The Democratic staff of a House of Representatives oversight committee urged members to focus on tempering speculation in oil markets as the most effective way to curb prices, according to a report on Monday.

The report prepared for the minority Democrats on the House Committee on Oversight and Government Reform said measures such as increasing domestic offshore drilling -- one of a host of recent legislative efforts meant to seek to reign in $4 gasoline prices -- would do little to curtail crude oil.

"Addressing excessive speculation offers the single most significant opportunity to reduce the price of gas for American consumers," according to the report for the committee, which has broad oversight of government policies.

"In order to make the most significant impact on lowering gas prices, the Committee's primary focus should be on countering the growing impact of excessive speculation, rather than pursuing the oil industry's priorities of increasing domestic drilling or repealing safety measures put in place after the devastating BP oil spill," the report said.

The report said excessive speculation in energy markets could be boosting prices by as much as 30 percent.

(Reporting by David Sheppard; editing by Russell Blinch and Jonathan Leff)