An EU investigation into suspected anti-competitive behaviour at Russian energy giant Gazprom - put on hold because of the Ukraine crisis - will resume, EU antitrust chief Joaquin Almunia has confirmed.

"Some work was done but was suspended because of the Ukraine crisis but this investigation will not stop," Joaquin Almunia told an International Bar Association conference.

Almunia did not mention when the EU's investigation will resume.

But Europe's next competition commissioner, Margrethe Vestager is expected to decide whether to continue the settlement talks, charge Gazprom with violating the bloc's antitrust rules or drop the case, Reuters reported. She takes over from Almunia in November.

The EU relies on Russia for around a third of its gas needs, and 40% of that is delivered via pipelines through Ukraine.

Gazprom, which supplies a quarter of Europe's gas needs, has been under EU investigation since September 2012 for alleged market abuses, including over-charging customers and abusing its dominant position to block rivals.

The company, the world's top gas producer, has been trying to settle the case by putting forward concessions since then. It has, however, opposed regulatory pressure to change the way it prices its gas in eastern Europe, which is the main concern of the EU regulators.