A supplementary credit facility of about $9.5 billion, arranged over the weekend by the International Monetary Fund, could extend over a maximum of five years.

In a press conference held early Sunday, IMF managing director H. J. Witteveen said that 14 industrial and oil exporting nations had agreed that the special pool of money might be available for as much as three years beyond the original two-year term planned for the loan.

The transcript of Witteveen's press conference, with details of the agreement, was made available here yesterday.

The special fund - which has been dubbed the Witteveen facility - is designed to help member countries with pressing balance of payments problems. The IMF has been running out of cash, and needed a temporary boost to provide the necessary resources, prior to the next increase in regular quotas (deposits) which will be sought next year.

Witteveen said the $9.5 billion, soon to be increased to at least $10 billion with loans from Kuwait and Nigeria, together with other resources will be enough "to meet all the needs that could arise in the next few years."

He said he hoped that the funds which at the moment is composed 55 per cent in loans by the industrial nations and 45 per cent by the oil-exporters, by the industrial countries, "could help mantain confidence in the financial system so that . . . other financial flows can continue and countries can also continue to borrow from the market."

The cash from the Witteveen facility will go to those countries whose payments difficulties are too large to be met through their regular borrowing rights at the IMF. Varying degrees of condition will be attached to the loans, with 12.5 per cent that any country might borrow available on the easiest conditions set by the IMF, and the balance on progressively tougher performance requirements.

Other points made at the press conference: