Nicaraguan Contra troops in the field will not be affected by deep cuts in administrative staff and expenses planned for the end of the month, a spokeswoman for the U.S.-backed rebels says.

"We are not closing - it's just a matter of trying to function with less cost," spokeswoman Marta Sacasa said late Tuesday.

Layoffs are expected at the Miami headquarters and at other Contra political offices, although some employees may continue as unpaid volunteers.

"By the 30th (of June), I understand nobody is sure who will continue working," Sacasa said, adding that the Contra directors have not announced the extent of the layoffs or the top-to-bottom "restructuring" that will accompany them.

She denied cutbacks were directly related to Congress' refusal to back the Reagan administration's full budget request for the Contras this year.