The Prince George's County School Board increased its wage offer to teachers for the second time yesterday despite complaints from some board members that offering the raises is unrealistic in a budget-cutting year, sources said.

The new proposal, agreed on in a lengthy closed board session Thursday night, was presented to the 7,000-member Prince George's County Education Association, bargaining agent for the teachers, yesterday. The union's negotiating team then decided to present the proposal to the union board of directors today.

The teachers have rejected two previous board proposals in a long and difficult negotiation that has been strained by the budgetary pressures on the board. The board must add whatever it gives the teachers in raises and benefits to a preliminary budget that county officials have already said is too high.

The original offer was a package that included a 3.3 percent wage increase, a substantially less than the 6.3 percent raise the teachers got as part of their current one-year contract, which expires June 30.

After the teachers rejected that proposal and threatened to declare an impasse in the negotiations, the board voted two weeks ago in a stormy session to raise the wage offer to at least 4.5 percent, and to grant the teachers an insurance program that would allow them to pay only minimal costs for prescription drugs. That total contract package, sources said, amounted to an increase of over 7 percent.

The teachers, who have sought a 5 percent wage increase, rejected that proposal. The board then instructed its staff to prepare a package that would grant teachers a 5 percent salary increase "while staying within President Carter's wage increase guidelines," which limit total increases to close to 7 percent.

Several board members including Susan B. Bieniasz and Angello I. Castelli protested that the increases would never be accepted by the County Council, which must approve the school board budget, in the first year of a voter-imposed revenueceiling.

Sources said some board members were also angered because a few members who are close to the teachers have been privately hammering out acceptable terms with the union outside of the formal negotiating process.

Board members who have favored the increases to the teachers have been Chairman Norman H. Saunders, Vice Chairman Jo Ann T. Bell, Lessources said. Board member A. James Thursday night, sources said.

Each 1 percent increase in the teacher's wage offer increases the price of the contract to the board by about $1.5 million, according to union Persident Toby Rich. Last year's teachers' contract cost the board more than $10 million.

Rich, board members, and schools spokesman John Aubuchon refused to comment on the details of the negotiations yesterday.