Tuesday's decree, signed by Prime Minister Viktor Orban, covers key firms in the power, gas and oil industries, as well as district heating firms and mining, along with gas pipeline operator FGSZ and a fuel and gas stockpiling association.
Hungary is about 85% reliant on Russian gas imports and 65% reliant on crude oil imports from Russia.
Foreign Minister Peter Szijjarto said earlier this month that Gazprom chief executive and Russia's deputy prime minister, Alexander Novak, had both assured him the company would fulfil obligations to Hungary set out in its long-term gas supply contract.
On Monday, Szijjarto said Hungary's gas storages were more than 39% full, which equals 2.7 billion cubic meters in store.
Under a deal with Gazprom signed last year, Hungary receives 3.5 billion cubic metres (bcm) of gas per year via Bulgaria and Serbia and a further 1 bcm via a pipeline from Austria. The deal runs for 15 years.
(Reporting by Krisztina Than; Editing by Clarence Fernandez and Michael Perry)