Thirty American organizations linked to mainline Protestant churches and to the Roman Catholic Church have formed a coalition - the Religious Working Group (RWG) on the World Bank and International Monetary Fund (IMF) - to seek greater justice in the global economy. Concern has grown among some church groups over the past decade that the policies of the World Bank and IMF - the world's two biggest lending institutions - have exacerbated the problems of communities in the developing world, devastated the environment, and put a debt noose around the necks of the poor. Members from RWG and other groups plan to publicize their cause at the annual meeting of the two banks Oct. 9-12 in Washington. Graham Barrett, spokesman for the World Bank said he was not familiar with the RWG. He says that the World Bank works successfully with thousands of non-governmental organizations worldwide, including churches. ''As the largest development bank in the world, we're doing our best to alleviate poverty, provide health care, education and to work with women and with persons with Aids.'' Much of the recent concern of church groups has been focused on Africa, where estimated debt of $164 billion has forced many of the continent's nations to stop investing in education, health, industry, and food production. The RWG has added its voice to a worldwide movement for reform of international financial institutions. The RWG aims to educate religious denominations and communities about debt and development issues. Hundreds of religious leaders have signed the RWG's declaration for change, which calls for a cancelation of debt owed by the poorest countries, an end to structural adjustment programs, and greater accountability by the two financial institutions. The RWG hopes that ''we as a people of faith can find some alternatives'' to the financial abyss confronting the poor, says Erich Mathias, program associate with the Joint Ministry in Africa for the Disciples of Christ and United Church of Christ in New York. In June members of the RWG travelled to Halifax, Nova Scotia, to lobby for world economic reform at the meeting of seven leading industrialized countries, the G-7 Summit.