Ireland's banks will likely need a further €3-4 billion over the coming years to meet international capital requirements.
This is according to an interview with the country's financial regulator, Matthew Elderfield, in German paper Boersen-Zeitung.
However, the Central Bank hopes the banks will be able to raise the money themselves instead of it being provided by the State.
The new capital would not be required for another five or six years.
Regulator Matthew Elderfield said in March that the looming Basel III rules would likely force banks to require more capital, although the Government hopes the majority state-owned sector will be in a position to raise the funds itself by then.
The Government had to pump €64 billion worth of capital into its banks after the bursting of a property bubble almost collapsed the sector and the Central Bank Governor Patrick Honohan said last week that the Irish banks remain adequately capitalised.
Asked if Irish banks need more capital, Elderfield, who is also a deputy governor at the Central Bank, said: "In the medium term they will certainly need more capital, if only because of the stricter international capital requirements."
"With regards to measuring capital and the question of which instruments count and which do not, the institutes must go even further," he said. "In the coming five to six years, the Irish banks should need a further €3-4 billion.''
He added that Ireland was making good progress with the stabilisation of its banks, but that "the banks also need more time to check their credit portfolio".
"They are not as far as they should be, their operative ability is not as strong as it could be," he said.
The banks are now struggling to return to profitability ahead of the so-called Basel III rules which will gradually require them to hold greater capital buffers by 2019.
In a speech to the Harvard Business School Alumni Club of Ireland on March 2, the Deputy Governor of Central had already said banks would need more capital.
"Where does that leave the banks' capital position for the future? We already know that over the medium term, in the period leading up to implementation of Basel 3 in 2019, that the banks will likely require more capital. At the two pillar banks, the elimination of deferred tax assets in the order of about €5 billion will have to be met through utilisation of taxable profits, or, to the extent that profits are not available, through additional capital. Therefore, the sooner the banks can be restored to profitability then the better they will be able to meet these medium term targets, ideally from market sources," Mr Elderfield said.
A spokesman for the Central Bank told RTE News: "As noted originally in a speech on March 2, the Irish banks (like those of other countries) need to take steps to strengthen their capital position over time to ensure full compliance with the revised Capital Requirements Directive. "The goal is that the banks should meet these more rigourous requirements through improving profitability through the transition period."