Dr. John Bell Condliffe, 90, professor emeritus of economics at the University of California at Berkeley and an authority on international monetary policy, died Wednesday at his home in Walnut Creek, Calif., after a heart attack.

Dr. Condliffe played a major role at the Bretton Woods, N.H., Monetary and Financial Conference in 1944, which laid the groundwork for establishment of such international economic and financial institutions as the International Monetary Fund and the World Bank.

In 1933, he wrote the final report of the World Economic Conference in London. In 1942, he wrote "Agenda for a Postwar World," which dealt with the connection between Germany's policies of high-tariff protectionism and military aggression.

From 1931 to 1937, Dr. Condliffe was a member of the Economic Intelligence Service for the League of Nations in Geneva, Switzerland. He had been a professor in New Zealand and at the University of Michigan and was a professor of commerce at the London School of Economics before joining the faculty of the University of California at Berkeley in 1940. He retired and was named professor emeritus in 1958.

Dr. Condliffe also was a consultant to many international institutions, including the Reserve Bank of New Zealand. He was a senior economist at the Stanford Research Institute from 1961 to 1967.

A native Australian, he was educated in New Zealand and earned bachelor's and doctor's degrees in economics from Canterbury College in Christchurch, New Zealand.

During World War I, he served with New Zealand's forces inEurope.

Dr. Condliffe's many publications include the World Economic Surveys of the League of Nations in the 1930s; "The Reconstruction of World Trade" and "The Commerce of Nations," published in the 1940s; "The Welfare State in New Zealand," 1959; "The Development of Australia," 1964; "Te Rangi Hiroa: The Life of Sir Peter Buck," 1972, and "Defunct Economists," published in 1973.

He was a member of the Royal Economic Society, the American Economic Association, the Economic Society of Australia and New Zealand, and the Cosmos Club in Washington.

Survivors include his wife, the former Olive Grace Mills of Walnut Creek, whom he married in 1916; a son, Peter, of Kensington; a daughter, Margaret Condliffe Kessler of Berkeley, nine grandchildren and seven great-grandchildren.

The family suggests that expressions of sympathy be in the form of contributions to the Margaret Condliffe Prize Fund at Canterbury University, Christchurch, New Zealand.