The Fairfax County School Board will push ahead with efforts to win approval of its five-year construction plan despite the county executive's contention that it could damage the government's valued AAA bond rating, school officials said last night.

The decision could set up a confrontation with the county Board of Supervisors, which must approve the submission of bond proposals for voter approval. Board of Supervisors Chairman John F. Herrity has said he thinks the school construction plan is "too large, and it's got to be cut back."

Superintendent Robert R. Spillane and School Board Chairman Mary E. Collier said last night that a controversial proposal to postpone 10 of the 16 school renovations included in the plan by a year or two would be dropped.

"It was ridiculous as far as I was concerned," Collier said. Spillane suggested that County Executive J. Hamilton Lambert, who works for the supervisors, should not have made his statements about the construction plan.

Assistant Superintendent Alton Hlavin had proposed postponing the renovations after Lambert warned that building all the projects called for under the proposed schedule would push county bond needs $73 million over the five-year guidelines set by the Board of Supervisors.

The guidelines call for the county to sell no more than $400 million in bonds over five years, with an annual target of no more than $80 million and an absolute ceiling of $100 million per year. The guidelines help the county preserve its AAA bond rating -- the highest possible -- which enable it to sell bonds at the lowest interest rate.

The construction plan adopted by the School Board on Jan. 23 would cover fiscal years 1987 to 1991 and cost $196 million. It calls for the building of eight schools and three special education centers, constructing additions to 11 elementary schools, renovating the 16 schools, and adding gymnasiums and music rooms at 11 elementary schools.

The proposal to postpone the renovations had prompted some critics, including former School Board member Toni Carney, to question whether the School Board was caving in to the Board of Supervisors rather than asserting the county's educational needs.

Yesterday, Spillane said Hlavin's proposal, which had been distributed to School Board members and reporters, was an "internal memo" never meant as a formal proposal.

As for Lambert's concerns about the size of the package, "the fact that he wanted some reductions was irrelevant," Spillane said. "We need those buildings and we're going to make sure that bond package is funded properly." Funding the plan is "going to be a problem they're [the supervisors] going to deal with," Spillane said. "We're going to send over our package. How it's funded is going to be worked out."

Kevin Bell, president of the County Council of PTAs, said the School Board's action "shows the School Board, and hopefully the county, has as much commitment to public schools as it does to the roads."

Spillane yesterday gave School Board members tentative alternative proposals for school bond packages to go to county voters Nov. 4 in what would be the first installment of the construction plan.

One would spend $118 million in two years to build seven schools, three special education centers and additions at 10 schools, fund renovations at nine schools, air-condition some older schools and buy a high school site. The second package would spend $137 million in three years to do the work in the other package, and add three renovations, an addition and planning funds for an intermediate school.