BRATISLAVA: Britain said on Tuesday it would oppose any EU plans to combine European forces into a single army or set up an EU military headquarters while London is still in the bloc.

At a meeting of EU defence ministers in Bratislava, Britain's Michael Fallon said it was up to NATO, not the European Union, to defend Europe against a more hostile Russia and that northern and eastern EU countries agreed.

France and Germany had hoped that Britons' decision to leave the EU, as well as London's need for goodwill in its exit negotiations, would leave the path open for common defence proposals that are meant to pull the remaining governments together. The proposals were presented on Tuesday.

But Britain's hardline position suggests Paris and Berlin may face a tougher time than diplomats expected to push through plans to bring together the EU's disparate military assets, develop technology and rely less on the United States.

Britain's concern is that the EU's ambitions could suck financial resources away from NATO, where allies have spent years cutting budgets following the 2008 financial crisis.

Most EU countries, including Germany and France, are members of the US-led alliance and contribute to EU and NATO rapid reaction forces.

The EU also needs Britain, one of the few European nations able to lead large military missions, as a partner.

"There are member states who would like to see...a single set of forces. That looks and sounds to me like a European army, and we would oppose that," Fallon told reporters.

"Europe is littered with HQs, what we don't need is another one."

Britain retains full voting rights until it leaves the European Union. Fallon said Sweden, the Netherlands, Poland, Latvia and Lithuania had also voiced concern about Franco-German proposals at the meeting, although it was not immediately possible to verify their positions.

At the meeting, France and Germany made the case for the EU's defence plan, searching for a coherent strategy that their leaders can formally back at a summit in December.

The proposals include increasing spending on military missions, jointly developing assets such as helicopters and drones, expanding peace-keeping abroad and building stronger defences against state-sponsored hackers in cyberspace.

Standing together on arrival, Germany's Defence Minister Ursula von der Leyen and her French counterpart Jean-Yves Le Drian were at pains to stress there were no plans for army of European soldiers wearing the same uniforms.

"On the contrary," von der Leyen said. "It is about bundling the various strengths of European countries to be ready to act together quickly."

She cited how Europe had struggled to coordinate support during the 2014 Ebola epidemic in West Africa. In 2011, the British and French air campaign in Libya also showed Europe's limits, as the operation quickly became reliant on a NATO-led operation including the United States, Canada and Norway for refuelling planes, logistics and military know-how.

EU's foreign policy chief Federica Mogherini, who has put forward her own proposals, said there was "nothing ideological" about what the bloc was trying to do.

Building on initiatives dating back to the late 1990s, the plans could strengthen the bloc's ability to respond without the help of the United States to challenges on its borders, such as failing states or a more aggressive Russia.

European military spending is a fraction of the United States' and only a handful of countries, including Britain, Estonia and Greece, spend generously on defence.

France is a major European military power and Germany has many military assets but has traditionally been cautious given its history in the 20th century's two world wars.

The diplomacy in European capitals over the coming months will be about showing London that stronger EU defences are in NATO's interest, according to Urmas Paet, a former Estonian foreign minister and now a lawmaker in the European Parliament.