SYDNEY, Dec 18 (Reuters) - Asian shares fell on Thursday as the tech sector took a beating on renewed angst about AI spending, while investors braced for a wave of central bank meetings set to underscore policy divergence worldwide.

Geopolitical tensions are roiling the commodities markets. Oil prices extended a rebound from five-year lows after President Donald Trump ordered a "blockade" of all sanctioned oil tankers entering and leaving Venezuela. Silver hit a new record that helped pull up gold.

Sterling nursed losses after an unexpected drop in UK inflation all but guaranteed a rate cut from the Bank of England later in the day.

The European Central Bank, the Norges Bank and Riksbank are also due to deliver their policy decisions on Thursday, with focus squarely on the outlook as all three are widely expected to hold rates steady. In the region, traders are bracing for a rate hike in Japan on Friday though there is less certainty about the pace of tightening next year.

MSCI's broadest index of Asia-Pacific shares outside Japan fell 0.5% as South Korea dropped 1.3% and Hong Kong's Hang Seng index slipped 0.5%. Japan's Nikkei was down 1.2%.

Nasdaq futures gained 0.3% and S&P 500 futures rose 0.2%, after a tech-led selloff on Wall Street as investors grappled with renewed concerns over record AI spending. Shares of AI bellwether Nvidia tumbled 3.8%.

Oracle plunged 5.4% after it announced an equity deal to support a data center project would not include a key partner Blue Owl Capital. The stock has shed almost 50% from mid-September when a deal with OpenAI sparked a 35% one-day rally.

"Oracle remained the primary source of anxiety... This latest setback deepened investor scepticism around Oracle's aggressive AI infrastructure buildout," said Tony Sycamore, analyst at IG, adding that he has now moved to a more neutral stance on the Nasdaq 100.

"Worries over soaring capex, heavy debt, construction delays, OpenAI's massive cash burn, and mixed Q2 earnings have eroded confidence, positioning Oracle as the poster child of fading AI infrastructure hype."

INFLATION SURPRISE FIRMS CASE FOR BOE RATE CUT

On the monetary policy front in the U.S., Federal Reserve Governor Christopher Waller, who is expected to be interviewed by Trump as a candidate for the next Fed chair, said the central bank has room to cut interest rates amid signs of job market weakness.

Investors are also watching out for a U.S. inflation report for November later in the day that will not include the month-on-month measure since a record government shutdown prevented data collection for October.

Forecasts are centred on an annual rise of 3% in core inflation last month.

In the forex markets, sterling held at $1.3374, having slumped to as far as $1.3313 overnight after data showed British inflation fell much more than forecast to 3.2% in November, its lowest since March. That all but cemented the case for a rate cut from the BOE later in the day, which is about 98% priced in.

The euro was steady at $1.1742, not far from a three-month top of $1.18, ahead of the European Central Bank policy decision where expectations are for no change.

Treasuries were largely steady. Two-year Treasury yields fell 1 basis point to 3.4725%, having budged little overnight, while the 10-year yield was flat at 4.1431%.

Oil prices gained for a second day after Trump's announcement of the Venezuela blockade with most exports from the country remaining on hold. U.S. crude rose 1.7% to $56.91 per barrel, while Brent crude futures were up 1.5% at $60.62 a barrel.

Spot gold prices slipped 0.3% to $4,330 per ounce, while silver also eased 0.2% to $66.17 per ounce but remained just a touch below a record high of $66.88 hit on Wednesday.

(Editing by Shri Navaratnam)