President Pusey said yesterday that Harvard will begin construction of a new undergraduate science center within three or four years if about $3 million in Federal government funds becomes available to the University.

Pusey said that the cost of such a facility for the chemistry, physics, and biology departments would be around $6 million, but that the University cannot raise the total amount from private resources.

NSF for Funds

"The most likely source of Federal money is the National Science Foundation," Pusey said. The NSF has a limited amount of funds available for university building construction on a matching grant basis.

Before any money is forthcoming from the NSF, an appropriations bill must be passed by the Congress. Pusey said that Harvard's application for funds will be before the NSF "as soon as the necessary money is authorised."

The College's science departments have been debating the possibility of a common undergraduate science center for about two years, but the last hold-out, the Chemistry Department, did not finally agree to the project until last fall.

The stumbling block to earlier agreement had been the Department's objection to an exclusively undergraduate center.

The departments involved have been meeting recently with Arthur D. Trottenberg '48, assistant Dean of the Faculty for Business Affairs, and other members of a special committee to discuss distribution of space and facilities within the Center.

No Plans Yet

Although no working diagrams are yet available, Pusey said yesterday that final plans could be prepared immediately if the necessary Federal money is authorized.

University officials expect the proposed Science Center to be between 11 and 15 stories high and have suggested the corner of Kirkland and Oxford Sts. (next to Lowell Lecture Hall) as the probable site of the building. A group of frame houses now on the site will soon be vacated by the Graduate School of Education and demolished.