Banks will need hundreds of billions of euros of extra capital following an agreement of tougher capital rules, ECB's Governing Council member and head of the Basel Committee on Banking Supervision Nout Wellink said.

"I hesitate a bit to mention numbers because it concerns a very long phase-in period that will take about eight years and numbers will change over time. It will be hundreds of billions (of euros)," Wellink told Dutch radio programme NOS Radio 1 Journaal on Monday.

"Partly they will have to retain profit for years which they cannot use to pay shareholders or bonuses. For another part, this will vary from bank to bank, they will have to get it from the capital market," Wellink said.