Brussels - European Union energy ministers were meeting in Brussels on Monday to discuss ways of dealing with the shortage of Russian gas arriving via Ukraine.

The supply is now expected to resume on Tuesday following a deal on gas monitors signed in Brussels by representatives of Gazprom, Russia's state-owned gas monopoly, and Ukraine's Naftogaz, whose pipelines are used by Moscow to deliver gas to Europe.

But the long-standing dispute between the two sides has already forced many European countries to dig into their reserves.

It has also sparked a row between Slovakia and neighbouring Austria over Bratislava's plans to meet its own shortfall by re-opening a Soviet-era nuclear reactor shut down by the EU for safety reasons.

As ministers met in Brussels, Austria lodged a formal complaint with the European Commission.

"It is unacceptable to push nuclear power through the back door because of the gas conflict," Austrian Environment Minister Nikolaus Berlakovich said of Slovakia's plans to switch on the reactor at the Bohunice plant.

Ferran Taraddellas, spokesman for EU Energy Commissioner Andris Piebalgs, said the reopening of the plant would be "a clear violation of Slovakia's (EU) accession treaty."

Officials said Piebalgs was due to hold talks with the relevant Slovak minister during the course of the afternoon.

Austria's government and public are strongly opposed to nuclear energy. The country's only nuclear power plant in Zwentendorf never went into operation, following a popular vote in 1978.

Slovak officials have since said that they will not restart the reactor if all parties sign the gas monitoring deal and Russia resumes supplies via Ukraine.

At their meeting in Brussels, EU ministers planned to shape "concrete measures" needed by the bloc to deal with the gas shortages and with future crises of this kind.

Ministers also planned to look at ways of improving the efficiency of the bloc's energy market, and at ways of strengthening solidarity between member states in the face of future crises, the Czech presidency said.

At the moment, Hungary is supplying some of its gas to EU hopeful Serbia, while Poland is sending trucks loaded with gas to Slovakia.

EU ministers were also expected to focus on the need for the bloc to develop alternative energy supplies, both by building pipelines to bypass Ukraine and Russia and by turning to other technologies, such as solar, wind and wave power.

"All European member states must do their bit so that more sources (of energy) are opened up and delivery routes created," Peter Hintze, a top official from the German economics ministry, said in Brussels.

British Environment Minister Ed Miliband said the EU should learn from the Russian-Ukrainian gas dispute by diversifying its supplies of gas and the sources of fuel that it uses. dpa