PRECIOUS-Gold firms as dollar softens, platinum rally falters

* Gold finds support from dollar, U.S. budget uncertainty

* South Africa supply concerns ease slightly for platinum

* Coming up: U.S. housing starts and building permits, Dec; 1330 GMT

(Adds quotes, updates prices, changes dateline from SINGAPORE)

LONDON, Jan 17 (Reuters) - Gold firmed on Thursday, supported by dollar weakness and ongoing concerns about U.S. debt talks, while a slight easing of South African supply worries sapped platinum's rally.

Spot gold rose 0.2 percent to $1,682.40 an ounce by 1147 GMT, trapped in tight ranges after stronger technical momentum subsided.

Spot platinum was flat at $1,682.86, pulling back from a three-month high of $1,699.50 hit on Tuesday.

Earlier this week, U.S. rating agency Fitch said the United States faces a "material risk" of losing its AAA status if there is a repeat of the wrangling seen in 2011 over raising the country's self-imposed debt ceiling.

"The broader debate that is going to happen in the U.S. in the run-up to the debt ceiling crisis point at the end of February is going to be supportive of gold. Talks of downgrades from the major rating agencies will be part of it," Credit Suisse analyst Tom Kendall said.

"This focuses people's attention on the longer-term stability of the U.S. debt situation and gets the market thinking about the longer-term value of the US dollar and benefits gold."

On the data front, investors will be watching U.S. housing numbers later in the day, as well as economic growth figures from China on Friday.

Dealers said physical buying interest, which had been strong at the start of the month in several Asian countries, ebbed.

"What we did see in the gold dips was strong physical demand across the Asian world including Thailand and India but since the rally back to current levels the physical market has definitely slowed," INTL Commodities CEO Jeff Rhodes said.

PLATINUM RALLY ERASED

Anglo American Platinum (Amplat) miners returned to work after an illegal walkout to protest against the world's top platinum producer's plan to cut 14,000 jobs, close two mines and sell another.

But analysts were still sounding positive about Platinum Group Metals (PGMs) - with platinum staying close to parity with bullion as demand for use in auto emissions was seen improving in China and the U.S. amid constrained supply.

"Potential for further supply shocks in the PGMs does have all the ingredients for an interesting few weeks in terms of prices," INTL Commodities Rhodes said.

"I think the premium of platinum over gold, once it gets through parity, it will pick up momentum and there is a significant chance of platinum moving back to a normal type of premium of at least $100," he added.

Spot palladium was up 0.2 percent at $724 an ounce, close to a 16-month high of $724.50 hit in the previous session. Silver stood at $31.47, up 0.1 percent, mirroring gold's upward move.

(Editing by Veronica Brown)