Britain warned its European Union partners not to water down rules that will force banks to build up larger safety cushions or to stop member states from requiring extra buffers.

The bloc is turning a global accord on bank capital known as Basel III into EU law but some countries want greater flexibility, arguing that not all the EU's 8,000 lenders have the same business model.

Banks would have to hold core capital equivalent to at least 7 percent of their risk-weighted assets by 2019.

It is vital that we resist any attempts to unpick this agreement in Europe through the Capital Requirements Directive, UK financial services minister Mark Hoban said in a speech during a visit to Brussels.

He also warned against allowing overly-flexible interpretations of the directive to allow lenders to scale back how much capital they must hold to withstand troubled markets.

It's why we fully support the European Central Bank's amendments to rectify the problems of double counting of insurance capital which as currently constructed, render the capital surcharge irrelevant for some of Europe's largest banks, Hoban said.

At the same time, jurisdictions must retain the right to apply higher levels of regulation to ensure financial stability in their own markets. This is particularly important for countries like the UK that are home to large global financial centres, Hoban added.

Britain is planning legislation to force the retail arms of banks like Barclays , Lloyds , HSBC and RBS to hold core capital of 10 percent, well above the Basel III minimum.

Hoban also attacked what critics say are protectionist EU plans to only allow investment firms from outside the bloc to offer their services to European customers if their home rules are equally strict.

In a global financial market, where capital is highly mobile, disproportionate and poor regulation will simply drive good capital to other destinations outside of Europe to the cost of European savers, investors and businesses, Hoban said.

(Reporting by Huw Jones; Editing by Mark Potter)