The European Union's current targets, introduced in 2022 after Russia slashed gas deliveries to Europe, require member countries to refill their storage caverns to 90% of capacity by November, with intermediate targets for February, May, July and September.

A draft European Commission document, due to be published next week, said: "The Commission will work with member states, also in the context of the gas storage regulation extension, to promote more coordinated and flexible gas storage refilling, including with dynamic targets."

This will "reduce system stress linked to gas storage refilling", added the document.

With EU benchmark gas prices climbing to hit two-year highs this month, countries including Germany and the Netherlands have called for the EU to soften its filling requirements - warning that fixed targets signal to the market that European buyers are obliged to buy, driving up gas prices and leaving a hefty bill for countries with large storage caverns.

A senior EU official told Reuters on Wednesday the plan was to use more flexible dates or filling levels when setting the targets, to avoid traders using the fixed refilling deadlines to speculate and drive up prices.

The Commission will publish a proposal by the end of March to extend the targets beyond 2025, when they are due to expire, the draft EU document said.

However, countries including Germany - which has the biggest storage caverns in the EU - and the Czech Republic have also said they want changes to the goals for this year.

The document is a draft of the European Commission's "Clean Industrial Deal", a package of measures to support European industries, which is due to be published on February 26.

EU gas storage sites dropped to 44% full over the weekend, after cold weather and reduced Russian supplies caused a faster drawdown of stocks, Gas Infrastructure Europe data shows.