* South Africa's Nov CPI cools

* Romania's Nov CPI cooler-than-expected

* Argentina plans to devalue peso, cut energy subsidies

* Stocks fall 0.6%, FX slip 0.1%

Dec 13 (Reuters) - Most emerging markets currencies and stocks nudged down on Wednesday ahead of the U.S. Federal Reserve's policy meeting, while Argentina's new government said it would weaken its peso by over 50% as part of its economic "shock therapy" plans.

MSCI's index tracking emerging markets stocks declined 0.6%, while a basket of currencies slipped 0.1% against the dollar by 0927 GMT.

Globally, markets focus will be on the Fed's last monetary policy meeting for the year, where it is expected to hold interest rates steady, while investors will be watching for comments on the timeline of rate cuts, if any.

A robust U.S. jobs report last week and a sticky inflation report on Tuesday will be some of the key economic indicators that sets the stage for the Fed's meet.

The benchmark 10-year U.S. Treasury yields slipped after the inflation report overnight, but steadied on Wednesday and was last seen at 4.1909%.

"U.S. Treasury yields remain one of the most important driving factors for emerging markets. The key question is whether Fed Chair Powell effectively pushes against market expectations for early rate cut," said Piotr Matys, senior FX analyst at In Touch Capital Markets.

"If Powell manages to dent expectations for the Fed to start cutting rates as soon as in spring, EM currencies are likely to soften," Matys added.

Grabbing investor eyeballs, Argentina will weaken its peso over 50% to 800 per dollar, cut energy subsidies, and cancel tenders of public works, new Economy Minister Luis Caputo said on Tuesday, as part of the economic measures aimed at fixing the country's worst crisis in decades.

The peso in the official market closed at 366.35 per dollar, while in the parallel black market it ended lower at 1050 to the dollar on Tuesday.

Argentina's central bank will announce measures related to monetary policy, its benchmark interest rate and debt on Wednesday, the economy ministry said in a post on X on Tuesday.

South African rand weakened 0.4% after headline consumer inflation fell to 5.5% year-on-year in November from 5.9% in October, data showed.

The country's October retail sales data is also due later in the day.

China stocks snapped a three-day rally as key messages at the Central Economic Work Conference, focusing on defusing risks but lacking new property stimulus, failed to excite investors.

The blue-chip CSI 300 index fell 1.7% and the Shanghai Composite Index declined 1.2%, while Hong Kong shares slid nearly 1%.

In Europe, Romania's November headline inflation cooled more-than-expected to 6.72% year-on-year from 8.07% the previous month, hitting its lowest rate since September 2021, data showed.

The Romanian leu was steady against the euro.

The Russian rouble hit a more than one-week high with the market looking ahead to an expected interest rate hike later this week.

The rouble was last seen 0.3% up to the dollar.

For GRAPHIC on emerging market FX performance in 2023, see http://tmsnrt.rs/2egbfVh For GRAPHIC on MSCI emerging index performance in 2023, see https://tmsnrt.rs/2OusNdX

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For RUSSIAN market report, see (Reporting by Siddarth S in Bengaluru; Editing by Alison Williams)