WASHINGTON, March 23 (Reuters) - The Commodity Futures Trading Commission needs to move quickly to establish position limits for metals such as gold and silver, Bart Chilton, the strongest proponent for position limits at the commission, said on Tuesday.

The CFTC, the country's top futures regulator, has already proposed a plan to limit the number of speculative contracts a trader can hold in the energy sector. The agency will hold a hearing on Thursday to see whether metals position limits are needed to avoid concentration and price manipulation.

"I think we should propose a rule on metals position limits now and move forward as swiftly as possible," said Chilton, a commissioner at the CFTC, in remarks obtained by Reuters that were prepared for a speech to metal investors.

"We need to get this type of regulation in place for these markets, to ensure that exchange-trading of metals accurately reflects the true economic prices of these commodities," he said in the remarks.

Chilton told Reuters in an interview he does not believe there is enough support now among commissioners to move forward on a proposal for metals position limits.

"I hope this (hearing) will be educational, informative and it may shift opinions in favor of position limits for metals," he told Reuters in an interview.

The CFTC has proposed a crack-down on concentration in energy markets with a proposal made in January, now out for public comment.

Three of the five commissioners -- Democrat Michael Dunn and Republicans Jill Sommers and Scott O'Malia -- have expressed concerns the energy proposal could drive trade to markets outside the CFTC's jurisdiction.

Chilton did not say which commissioners he thinks have reservations about metals position limits.

For his part, Chilton said he supported position limits for all commodities of limited supply -- including energy, metals and soft agricultural commodities such as sugar and coffee.

He said an individual trader holding 20 or 40 percent of a open interest in any given market in metals "is too high."

Metal traders said CFTC-enforced position limits could sharply reduce liquidity.

SILVER PROBE A "VALUABLE ENDEAVOR"

In his speech, Chilton said the CFTC is making progress on an investigation it began in September 2008 looking into alleged price manipulation in the silver market. The CFTC has taken testimony from dozens of witnesses and reviewed tens of thousands of documents, he said.

Chilton, without disclosing details of the review, said it has been "a valuable endeavor.

"We have looked at the silver market like we have never before and I think there is a window of success that has been opened for understanding about what has been going on and why," he said.

Chilton also said he has proposed establishing an office of consumer affairs at CFTC to ensure individuals who contact the agency get responses.

"A consumer affairs section would help address the misperception held by some that we are an unresponsive government agency," he said.