Earlier on Wednesday, Germany activated the 'early warning phase' of an emergency plan to manage gas supplies in case of a disruption or halt in supplies from Russia.

"Italy is monitoring developments before taking any decision," the source said.

Italy imports around 30 bcm of gas from Russia every year - some 40% of its total gas imports - and is looking to diversify its energy supplies following Moscow's invasion of Ukraine.

Last week President Vladimir Putin demanded Europe pay for its gas exports in roubles in retaliation for the West imposing sanctions on Russia for its invasion of Ukraine. Western nations have so far rejected Moscow's demand for a currency switch.

Russia has not said when the currency change will take effect but was expected to unveil its plans for rouble payments on Thursday.

But on Wednesday the Kremlin said it would not immediately demand that buyers pay for its gas exports in roubles.

Italy's existing gas emergency protocol envisages three stages going from a state of pre-alert, imposed at the end of February after the Russian invasion of Ukraine, before moving to one of alert and then a state of emergency.

While the first two stages essentially imply monitoring with normal market rules applying, triggering a state of emergency allows measures like accessing strategic gas reserves and rationing by limiting supplies to some industry users.

"Russian gas flows are regular," a spokesman for Italian gas transport group Snam said on Wednesday.

(Reporting by Stephen Jewkes; Editing by Keith Weir)