Russian gas exports via Soviet-era pipelines running through Ukraine came to a halt on New Year's Day, marking the end of decades of Moscow's dominance over Europe's energy markets.

The gas had kept flowing despite nearly three years of war, but Russia's gas firm Gazprom said it had stopped after Ukraine refused to renew a transit agreement.

The widely-expected stoppage will not impact prices for consumers in the European Union - unlike in 2022, when falling supplies from Russia sent prices to record highs, worsened a cost-of-living crisis and hit the bloc's competitiveness.

The last remaining EU buyers of Russian gas via Ukraine, such as Slovakia and Austria, have arranged alternative supplies, while Hungary will keep receiving Russian gas via the TurkStream pipeline under the Black Sea.

But Transdniestria, a breakaway pro-Russian region of Ukraine's neighbour Moldova also reliant on the transit flows, cut off heating and hot water supplies to households early on Wednesday.

Local energy company Tirasteploenergo urged residents to dress warmly, hang blankets or thick curtains over windows and balcony doors, and use electric heaters.

The European Commission said the EU had prepared for the cut-off.

"The European gas infrastructure is flexible enough to provide gas of non-Russian origin," a spokesperson for the Commission said.

"It has been reinforced with significant new LNG (liquefied natural gas) import capacities since 2022."

Russia and the former Soviet Union spent half a century building up a major share of the European gas market, which at its peak stood at around 35 percent. But the EU has slashed its dependence on Russian energy since the start of the war in Ukraine by buying more piped gas from Norway, and LNG from Qatar and the United States.

Ukraine, which refused to extend the transit deal, said Europe had already made the decision to abandon Russian gas.

"We stopped the transit of Russian gas. This is a historic event. Russia is losing its markets, it will suffer financial losses," Ukraine's Energy Minister German Galushchenko said in a statement. (Reuters)