In order to head off a financial crisis, Archbishop Peter L. Gerety of Newark has asked all parishes in the Catholic archdiocese to pool their day-to-day operating money into a new "cash management program."

The pooling of the daily revenue and expense monies of the 252 parishes would amount to an estimated $70 million, archdiocesan sources said.

Gerety explained that the pooling of resources "will place the archdiocese in a stronger position when dealing with banks and other financial institutions." He said that the present effort to renegotiate the archdiocese's $20.4 million loan with five New Jersey banks is at a "critical stage." He said a show of solidarity by the parishes is important at this time.

The original loan, secured in 1976, principally to cover operating defincits of the archdiocesan regional high schools, was for $22.5 million, payable over a 15-year period at an interest rate of 1 percent over prime. At that time, the prime rate was 6.75 percent.

Thus far, the archdiocese has paid more than $4.3 million in interest and $2 million on the principal. The archdiocese still owes more than $20.4 million, and the interest rate has jumped to 11.5 percent.

Father John Petillo, cochancellor of the archdiocese, said the primary purpose of the new fund is to "marshall the cash resources that exist in all parishes into a unified, comprehensive, coordinated fund, just as any other large corporation would od."

Archbishop Gerety stressed that "the money pooled will not become chancery funds. Complete control over individual cash balances will, and must, remain with each pastor," he said.

The Archdiocese will take a percentage of the interest earned by the fund to pay administrative costs, but individual parishes can expect to receive a substantially higher yield through this program than they could achieve on their own.

The archdiocese, which serves 1.5 million Catholics in four New Jersey counties, is now exploring the administration of the money-pool plan with a variety of banks, but has not yet made a decision.