The National Treasury Management Agency is taking over various responsibilities from the Department of Finance, including managing the Government's stakes in the banks.
According to a statement this evening the NTMA will now hold talks on capital needs with the institutions covered by the NAMA legislation.
Among the other responsibilities it is assuming, the NTMA will also hold discussions with financial institutions on their realignment or restructuring within the banking sector.
It will manage the Minister for Finance's shareholding in the banks, advise on banking matters, and crisis prevention, management and resolution.
Finance Minister Brian Lenihan said his department and the NTMA already worked closely together, and that both organisations' resources needed to be adjusted to deal with the evolution of the banking crisis.
He said that in future more work could be divided between the NTMA and the Finance Department.