The Episcopal bishop of Newark angrily broke off relations with the Roman Catholic Church yesterday to protest last month's offer by the Vatican of refuge for rebel Episcopalians who have left their church because of women priests.

Assailing what he termed the Vatican's "medieval ecclesiastical arrogance," Bishop John Shelby Spong denounced the Roman Catholic Church's offer last month to accept the dissident Episcopalians into its fold, calling it a part of the Catholic Church's "continuing sexist oppression of women."

The unexpected offer by the Vatican has caused considerable confusion and even consternation.

Spong's reaction is certainly the most outspoken thus far. Coming as it does from the head of one of the larger and more visible dioceses of the Episcopal Church, it is expected to be taken seriously. It may encourage others in the church, who have thus far grumbled quietly, to end their reluctance to critisize publicly another church.

Newark's Roman Catholic Archbishop Peter Gerety issued a statement saying he regretted "exceedingly that Bishop Spong feels obliged to postpone our conversations which have been looking toward convent relationships between our two communions." He expressed hope that "friendly relations"" would soon be reestablished.

Newark's Episcopalians and Catholics of the Newark and Paterson (N.j.) diocese have been engaged in enumencical talks, seeking common ground in the two branches of Christianity, for more than a year. Spong, who was known as a "liberal when he was rector of Richmond's prestigiuos St. Paul's parish before he was elected bishop three years ago, has been a vigorous defender and advocate of women priests within his denomination. At the same time, he has been deeply involved in a variety of ecnmenical activities.

In his statement yesterday, however, he said that if it came to a choice between the two emphases, "I would take my stand beside women priests . . . before mourning the loss of an ecumenical dialoue with a church that seems to be the area of human sexualtity to be mnaching firmly into the 19th century."

Late last month the Roman Catholic Church announced that it was making special provisions to receive into membership with a "common identity" the Episcopal dissidents who dropped out because of the women priests and revisions in the Anglican Book of Common Prayer. That offer included the provision that the former Episcopal priests, including these who are married, may be reordained into the Roman Church. However, they may not remarry if their present wife dies, and they are not eligible to serve as bishops.

Sprong said he has broken off the talks set for January because, in the light of the Catholic offer to the dissident Episcopalians, "a continuation of conversations aimed at a covenant relatioships might be interpreted as a violation of the integrity of the Episcopal Church or as an insult to or comprise of our women priests."

Spong said he showed a copy of his proposed statement to Gerety before he released it and modified it somewhat as a result of Gerety's suggestions. According to Spong, the relationship between the two bishops, both of them librals, has been "extremely cordial."

Discussing his reasons for issuing his attack on the Roman Catholic Church, Spong said in a telephone interview, "I felt something had to be done or the integrity of women priests -- would be called into question."

In his statement, Spong also deplored the Vatican's censuring of theologian Hans Kuend earlier this year as "the assumption by the Catholic herarchy that their understanding of the truth . . .

"If there is no room in Rome for theological debate among Roman Catholics," he said, "let us be honest and say there is no room for such discussion between Protestants and Roman Catholics," he continued.

On the issue of the Episcopal Church's decision four years ago to admit women to the priesthood, Spong said that such momentous changes "always take time to be absorbes. That absorption process was well under way," he said, "when this clumsy intervention into the Episcopal tensions was introduced" by the Roman Catholics.

"If the Episcopal Church must fight our sister Roman communion in order to affirm the full role of women in the life of the church, then sadly we will do so," he said.