The European Commission put forward draft legislation that would pour 500 million euros ($550 million) from the EU budget into increasing ammunition production.

EU internal market commissioner Thierry Breton said he hoped the proposal would become law by the end of next month.

The spending proposal comes as the bloc seeks to supply one million artillery shells to Ukraine over the next 12 months, at a cost of two billion euros.

The plan "will help supply more ammunition for Ukraine to defend its citizens and it will also strengthen our European defence capabilities," commission chief Ursula von der Leyen said.

"We stand by our promise to support Ukraine and its people, for as long as it takes," she said.

Ukraine has been burning through thousands of shells a day and has complained that its troops have had to ration their usage due to shortages.

The European Union is stepping up in a three-pronged strategy.

Member states are delivering more to Ukraine from existing stocks, with up to one billion euros of the cost covered from an EU fund called the European Peace Facility (EPF).

The bloc is also looking to jointly procure more ammunition for Ukraine, paid for by another one billion euros in EPF money.

Wednesday's plan to ramp up ammunition production in Europe is the third prong, which comes from different funding.

The draft legislation, called the Act in Support of Ammunition Production (ASAP), proposes tapping the EU's European Defence Fund and other budget lines.

Breton said that, along with "co-financing" by EU member states, the overall European bump-up in ammunition production would amount to "at least one billion" euros.

He said he was touring all of Europe's defence production sites to find ways to cut a timeline of "maybe two years, three years... to 12 months" as the plan tries to turn around decades of underinvestment.

The urgency was to "mobilise member states so that they will be comfortable giving their stocks immediately" with confidence that they would be replenished by the boosted production, Breton said.

The EU cash would go towards financing new production lines for howitzer shells and missiles, stepping up gunpowder output and refitting old ammunition.

Diplomats from some EU countries have expressed doubts over Europe's capabilities to produce enough ammunition, but Breton and other officials in Brussels insisted it can reach the target.