(Correct lead to clarify that gas flows from Nord Stream into Opal, adds background in paras 3-4)
* Opal crucial for boosting Nord Stream undersea shipments
* Gazprom already has exemption to use half of Opal
By Barbara Lewis and Vladimir Soldatkin
BRUSSELS/MOSCOW, Dec 6 (Reuters) - EU regulators expect to make a decision early next year on how much Russian gas can flow from Gazprom's Nord Stream pipeline through Germany's Opal link, EU officials said on Friday.
The Russian gas export monopoly's access to the 470 kilometre (290 mile) Opal pipeline, from Germany to the Czech Republic, is limited because of the EU's Third Energy Package legislation, which aims to prevent firms that already dominate supply from dominating transport networks as well.
Gazprom has been pressuring the European Union to lift restrictions on its use of the Opal pipeline, which is crucial for increasing Russian supplies from Nord Stream directly to Central Europe.
Nord Stream, which links Russia to Germany via the Baltic Sea, is designed to bypass countries including Ukraine in the shipment of Russian gas to Europe.
EU officials say Russia already has been allowed to use 50 percent of the Opal pipeline under an existing exemption, with the proviso that the rest of its capacity should be used for the Czech market.
The overall capacity of the Nord Stream pipeline is 55 billion cubic metres (bcm) a year, but Gazprom, which heads the consortium of shareholders, has been pumping only around half that.
According to Nord Stream data, it shipped 21.3 bcm in January-November, almost double the year-earlier volumes.
"Russia has accepted that Opal is on EU territory. That's why EU legislation is the crucial thing. They have asked formally for an exemption," Marlene Holzner, a spokeswoman for the European Commission, told reporters.
Gazprom is not happy with the limit and is seeking more capacity, EU officials said.
In November, the Commission, the EU executive, began reviewing the previous exemption. Under EU law, it has an initial two months to make a decision, although under some circumstances, a further two months of can be granted.
The Commission says Nord Stream is of a different status from the giant South Stream pipeline project to ship up to 63 bcm a year of gas via the Black Sea, which EU officials have said has a great deal of work to do to conform with EU law.
Holzner said the Commission would like Russia "to formally ask for an exemption" for South Stream.
Russia's deputy energy minister, Anatoly Yanovsky, said that Russia had received a letter from the Commission regarding South Stream's legal status.
"We obviously would enter into a dialogue with our partners, strictly adhering to the norms of the international law," he said, without elaborating. (additional reporting by Katya Golubkova; editing by Jane Baird)