A top official at the Commodity Futures Trading Commission on Thursday pushed the agency to act quickly on a long-awaited plan to limit speculative positions held by commodity traders.

The regulator, which has a mid-January deadline, has been pushing back the date to propose new speculative limits in energy and metals markets, and so far has not given a time for when it will be introduced.

This proposal should be discussed on December 9th at the commission's next meeting; a proposal should be put out for public comment as soon as possible; and we should commit to meeting the statutory deadline, said Bart Chilton, a CFTC commissioner.

We can always find excuses, justifications, or pretexts for inaction -- this rule is too important to let any of those get in the way of fulfilling our statutory responsibilities, and keeping our promise, he said.

The Wall Street reform law gives the CFTC power to impose position limits for all commodities across exchange-traded and over-the-counter markets.

It gave the CFTC 180 days to have the new rule in place for energy and metals markets, and 270 days for limits in agricultural markets.

The CFTC has grappled with how to police and set the limits, part of a broader push by the agency to implement rules to overhaul the $600 trillion over-the-counter swaps market under the Dodd-Frank financial law enacted in July.

Fellow CFTC commissioners Scott O'Malia and Jill Sommers were less optimistic about meeting the January deadline.

At this point we're not going to make the deadline, Sommers told Reuters on Wednesday. I don't see how we make the January deadline.

Once the CFTC introduces the rule, the agency is required to open it to public comment for at least 30 days, review those comments, determine any revisions, then finalize it.

The CFTC has two meetings in December to propose new rules -- December 9 and 16 -- and a pair in January. The December 9 meeting calls for the agency to discuss swap execution facilities rules and an exemption from mandatory clearing requirements.

(Editing by Dale Hudson)