The European Commission on Tuesday proposed spending €500 million to finance joint defence purchases among member states to replenish weapons stocks following Russia's invasion of Ukraine.

In a first for the European Union, the fund would draw on the EU budget over the next two years and would help countries replace depleted stockpiles after arms shipments to Ukraine emptied arsenals.

"(EU countries) have drawn on their stocks of ammunition, light and heavy artillery, anti-aircraft and anti-tank defence systems, and even armoured vehicles and tanks," European Commissioner Thierry Breton said.

"This has created a de facto vulnerability that now needs to be addressed urgently," he warned.

Defence spending in Europe varies widely among the 27 EU member states and lacks coordination, drawing criticism that neighbouring countries often double up on investments, driving up prices.

Debate has raged for decades over whether Brussels should bring in more unity on defence matters. EU member nations -- most of which are also NATO allies -- have often been reluctant to agree moves to integrate military capabilities.

But under the impulse of France, ambitions on common defence have gathered steam in recent years, including a 7.9-billion-euro defence fund agreed last year, in a separate programme.

Under the latest proposal, the fund would accept purchase requests from at least three member states at a time when spending on weapons is ramping up due to the war in Ukraine.

The commission said replenishing stockpiles, replacing Soviet-era legacy systems and reinforcing air and missile defence systems were the top priorities.