A D. C. City Council committee voted yesterday to assure apartment renters the first option to buy their buildings before they may be offered for sale to condominium converters or other new landlords.

The Housing and Economic Development Committee added the provision to legislation it approved two weeks ago that would-regulate and restrict the shift of rental properties into condominiums.

The action, recommended by committee chairman Willie J. Hardy (D-Ward 7), was a victory for tenant groups. They were upset that the provision was omitted from the original version of the bill.

Yesterday's action, taken by an unrecorded voice vote, cleared the measure for action by the full council, probably June 3. Until its enactment, most condo conversions are restricted by a stop-gap mortorium law that will expire next month.

The legislation approved by the council panel yesterday would require a landlord to offer an apartment project to its tenants at least 60 days before putting it on the open market for sale either to a new apartment operator or to a condo converter. It also would provide a similar time for the tenants to arrange financing.

If enacted, the bill would end the right of an apartment owner to obtain a certificate permitting a condo conversion and then selling the property at a price reflecting the certicate's value to a developer who actually carries out the conversion. In the future, only the actual owner could apply for the certificate.

Tenant spokesmen, supported by committee members David A. Clarke (D-Ward 1) and John A. Wilson (D-Ward 2), protested the omission of the option-to-buy provision when the committee first approved the bill two weeks ago.

Hardy said then that it was excluded because an identical provision is part of the existing rent control law and probably would be included when the rent law is extended beyond its expiration in September. Hardy said she put it back in the condo bill yesterday because her colleagues wanted it there.

Several tenant groups around the city have taken advantage of the existing purchase option requirement to form their own condominium or cooperative organizations, blocking potential acquistitions by outside converters.