UPDATE 1-Hungary says Russian gas supplies via Ukraine stopped

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BUDAPEST Jan 6 (Reuters) - Russian gas shipments via Ukraine to Hungary halted on Tuesday and the Hungarian government said it would ask some power plants to switch to alternative fuel by 1000 GMT on Wednesday.

"I would like to inform you that gas shipments from Ukraine continuously declined today and at 1430 GMT they completely stopped," Transport and Energy Minister Csaba Molnar told a news conference.

The government would consider freeing up strategic gas reserves and make a decision on Wednesday morning if necessary, he said..

"There is an increasing likelihood ... that tomorrow we may have a situation, depending on news overnight ... that we will have to impose restrictions in the first category, that of large (gas) users," the minister added.

Molnar said Hungary would notify Serbia and Bosnia that it was unable to provide transit gas shipments as Russian gas imports via Ukraine had stopped.

Molnar said Hungary would write a letter to Ukraine, Russia, and the EU presidency the Czech Republic saying a dispute over gas between two countries must not be allowed to pose a threat to the gas supply of other European countries.

Hungary's gas imports via a pipeline from Austria, which has a capacity of 6-7 million cubic metres a day, have also dropped to around 3 million cubic metres.

Hungary's daily gas consumption was estimated at 68 million cubic metres on Tuesday, and it would be about the same on Wednesday, the Chief Executive of MOL's MOLB.BU gas transmission arm, Foldgazszallito Zrt, said.

"At the moment, we think we just have enough domestic resources to cover this (daily) need ... including the 3 million cubic metres of gas which we still receive (via Austria)," CEO Janos Zsuga said.

Hungary's annual gas consumption is around 13-14 billion cubic metres. Around 80 percent comes from Russia on pipelines through Ukraine and the rest is from domestic production.

The country has about 3.8 billion cubic metres of gas in storage, including strategic reserves.

Zsuga said if gas consumption remained at current levels, and imports from Ukraine did not resume, Hungary had enough gas reserves to cover domestic needs for several weeks.

"If (daily) gas consumption increases ... then we will have to impose restrictions on consumers," he added.

Hungary can pump about 51.5 million cubic metres of gas per day into the network from storage. The weather has been very cold this week, with temperatures dropping below minus 10 degrees Celsius during the night. (Reporting by Krisztina Than; Editing by Giles Elgood)