WASHINGTON — Roman Catholic opposition to the health care overhaul package is crumbling, with some church officials and lawmakers concluding that their long-sought goal of health care overhaul trumps the desire to adopt the severest restrictions on abortion funding.

A coalition of 59,000 nuns released a letter yesterday calling on Congress to approve the overhaul, defying the US Conference of Catholic Bishops, which opposes the measure. The Catholic Health Association, which represents 1,200 Catholic hospitals, has endorsed the package, as have Catholics United and Catholic groups promoting social justice.

That split mirrors a division among some antiabortion US representatives. In preparing to cast perhaps one of the most important votes on a domestic issue in their careers, they are wrestling with questions that strike at the core of their beliefs and that threaten to embolden voters in November.

Ardently antiabortion Representative Dale Kildee, a Michigan Democrat who once studied in a Catholic seminary, said yesterday he will vote for the package despite language that some believe is not strict enough in ensuring that no federal funds are used for abortions.

Another antiabortion Catholic lawmaker, Representative James Oberstar, Democrat of Minnesota, said he is likely to vote for it. Several other antiabortion lawmakers are undecided but say they will not let the abortion issue sway their votes.

The political fissure among prominent Catholics has buoyed the hopes of Democratic leaders that they will be able to enlist enough votes to approve a health care bill this weekend. Abortion has been a central issue in the debate and could make the difference in a close vote.