Officials at three Prince George's hospitals vowed yesterday that the facilities would remain "fully operational" despite a planned strike by registered nurses set to begin at 7 o'clock this morning.

Members of the Maryland Nurses Association late Saturday rejected the latest contract offer from the management corporation that runs the Prince George's General and Greater Laurel-Beltsville hospitals and the Bowie Health Center. The local chapter of the association, which represents 650 nurses at the three hospitals, voted Saturday to set up picket lines this morning.

A corporation spokesman said hospital contingency plans include use of supervisory personnel and an unspecified number of substitute nurses, including some not connected with other hospitals, to fill vacancies when the day shift begins at 7.

The plans are "fluid," spokesman Mike Canning said, because corporation officials are predicting that a number of the registered nurses will report for work despite the strike.

But a union spokeswoman said that management is "severely underestimating the number of nurses that will walk. They are hoping we really don't have it together." She warned that despite management plans, "anyone who decides to use the hospital will not have a licensed nurse at their bedside."

Bargaining between the nurses and the Community Hospital and Health Care Systems Corp., a new private non-profit corporation that runs the former county-owned health facilities, broke down Friday night over the issues of union security and pay.

"We at this point have nothing further to negotiate," Canning said. "We've made our last and final offer."

That offer would increase nurses' hourly wages by 35 cents immediately and another 35 cents next July. The 17-month contract would, on average, increase nurses' salaries by about $2,000, Canning said. Salaries currently range between $17,300 and $23,300, said Carolyn Larkin, president of the local chapter of the nurses association.

Larkin said the nurses wanted the second 35-cent increase to begin in February and were asking for a shorter contract period. Larkin also maintained that the corporation's objection to a proposed agency shop provision, under which all new nurses would be required to join the union or pay a fee to the union, was unfair. The bulk of the hospitals' employes already belong to Local 63 of the Brotherhood of Firemen and Oilers, which has such a contract provision, she said.

Hospital corporation president Robert J. Brady announced yesterday that any registered nurses reporting for work today will automatically receive wage increases proposed in the latest management offer.

"It's pretty clear that all of the nurses won't participate in the job action," Canning said. "In fact, a number of them asked us whether they could picket and work."

Canning said that the hospitals are expected to operate normally. Prince George's Fire Department and rescue ambulances have been instructed to continue to bring in patients as usual, he said.