A Basel Committee proposal to impose tougher capital requirements on up to 30 global banks was approved on Saturday.The approval suggests that the last major battle over the shape of new global banking rules may be over.The Group of Governors and Heads of Supervision (GHOS), which oversees the Basel Committee on Banking Supervision, announced on Saturday that members had agreed on a plan to deal with "global systemically important banks", or G-SIBs*. These G-SIBs are to be subjected to tougher capital requirements because it is believed their failure would likely cause the greatest long-term damage to the global financial system. The G-SIBs will need to hold additional tier-one equity equivalent to between 1.0 and 2.5 per cent of assets, depending on their size and influence. This capital will be on top of the 7.0 per cent of assets that the Basel III framework requires all banks to hold as tier-one capital.A number of major banks believe this will penalise them compared with their smaller competitors.The G-SIBs would be designated based on size, interconnectedness, lack of substitutability, global (cross-jurisdictional) activity and complexity, the GHOS statement said. It also said a further 1.0 per cent additional capital requirement could be imposed if necessary -  a clear encouragement for banking giants not to merge.The tougher requirements would be phased in between 2016 and 2019, the GHOS statement said.Reports after the meeting suggested the plan would affect 28 to 30 major global players. That group is almost certainly too small to include any Australian banks. Australian representatives, including Reserve Bank assistant governor Malcolm Edey, attended the Basel Committee meeting held on Thursday and Friday of last week, ahead of the GHOS meeting.The GHOS will submit its plan to the Financial Stability Board, representing the G20 group of major economies. It meets on 18 July.(* The G-SIBs acronym is one letter shorter than the term it replaces, G-SIFIs, which stood for "global systemically important financial institutions".)