International banks threw their weight behind plans to support Greece with the help of the private sector on Friday, detailing options such as a roll-over of debt, extension of maturities and debt buy-backs.

A small number of options were being discussed, the Institute of International Finance (IIF) lobby group said, with the aim of providing significant cash-flow support to Greece on a voluntary basis.

These options will include a roll-over or extension of maturities and the re-investment of creditor claims into long-dated instruments with principal collateralization, the IIF said in a statement.

In addition, it would be important to consider possible debt buyback proposals, which could, along with further fiscal adjustment, begin to reduce the stock of debt.

The IIF is playing an informal role coordinating international banks to reach consensus about private-sector involvement in a bailout of debt-ridden Greece.

French banks, the most exposed to the Greek debt crisis, reached an outline agreement to roll over holdings of maturing Greek bonds this week, as part of a wider European plan to avoid sovereign default.

(Reporting by Douwe Miedema; Editing by Steve Slater)