When Poland last month accused Russian natural gas exporter Gazprom of denying it the supplies it wanted, something did not quite add up: Poland did not need all the gas it was asking for and would have had nowhere to put it.

This led some traders in the energy market to conclude that Poland has been trying to discredit Gazprom's reliability as an energy supplier ahead of re-negotiation of a long-term gas contract next month.

Poland could argue that Gazprom should charge a lower price if it cannot fully meet its contractual obligations.