WARSAW, March 23 (Reuters) - Central European currencies weakened on Monday as an escalation of the conflict in the Middle East strengthened risk aversion and demand for the safe-haven dollar.

Hopes for an off-ramp to hostilities in the Middle East dimmed over the weekend, with U.S. President Donald Trump threatening to strike Iran's electricity grid and Tehran vowing to hit back at the infrastructure of its neighbours.

As a result, the dollar index =USD, which measures the U.S. currency against a basket of peers, rose 0.22% to 99.77.

"Donald Trump's ultimatum to Iran, expiring Monday evening, regarding unblocking the Strait of Hormuz, and the accompanying threats of attacks on energy infrastructure, are intensifying global risk aversion on Monday morning," PKO BP said.

"This is supporting dollar appreciation and putting pressure on emerging market currencies, including the Polish zloty... Further developments in the conflict in the Persian Gulf will remain crucial for investor sentiment and trend direction."

The Polish zloty EURPLN= weakened by 0.2% to 4.2850 by 0909 GMT on Monday.

Moody's completed its review of Poland's rating on Friday, keeping it at "A2" with a negative outlook. The ratings agency expects Poland's GDP growth to reach 3.7% in 2026, compared to the previous forecast of 3.2%.

Elsewhere, the Czech crown EURCZK= was a touch weaker at 24.5310 per euro, after Czech National Bank Governor Ales Michl's press conference on Thursday turned out to be less hawkish in tone than many analysts had expected.

The Hungarian forint EURHUF= lost 0.3% to 394.30 per euro ahead of a central bank meeting on Tuesday.

The National Bank of Hungary is widely expected to leave its base rate steady at 6.25% HUINT=ECI amid a sharp rise in projected inflation driven by an energy price shock caused by the conflict in the Middle East.

"In Hungary, prior to the start of the Iran war we had expected another 25 bp cut in March, but we recently changed our call and now expect the NBH to stay on hold at +6.25% (in line with consensus)," Goldman Sachs said in a note to clients.

"We expect the NBH to maintain a cautious policy stance, driven by the deterioration in global risk sentiment, the recent HUF weakness, and a higher near-term inflation trajectory from energy price pass-through."

Risk aversion due to the situation in the Middle East hit global stock markets, with bourses in the region following them down with falls from 1.3% in Budapest .BUX to 2.7% in Warsaw WIG20.

(Reporting by Anna Wlodarczak-Semczuk in Warsaw and Krisztina Than in Budapest; Editing by Sharon Singleton)

((anna.wlodarczak@thomsonreuters.com;))