On the strength of Mayor Alfred E. Vellucci's support, the Cambridge City Council last night gave preliminary approval to two controversial housing ordinances, one which attempts to clarify the council's original intention in passing anti-condominium legislation nearly three years ago, and a second which would provide a special exemption from that code to a group of tenants at a Linnaean St. building.

In a housing policy initiative released three weeks ago shortly after his election as mayor. Vellucci called for a moratorium on all condominium-related debates in the council.

But he said last night that "you've got to clear the deck in order to get on with housing for poor people."

The Linnaean St. case, where a group of residents have sought special city council action that would exempt them from Cambridge's tough ordinances preventing the conversion of rent controlled apartments to condominiums, was a major issue in last fall's council election campaign.

"The landlords decided last year to make a test case" of the Linnaean St. residents," Cambridge Civic Association (CCA) Councilor David Wylie said last night. He added that the ordinance approved by the council last night could potentially prove "very destructive" to the city's overall condo conversion ban be cause the exemption has the effect of "treating similar cases dissimilarly."

Independent Councilor Daniel Clinton sponsored the exemption ordinance which authorizes and directs the rent control board to grant conversion permits to the Linnaean residents without a hearing. The rent control board has in the past refused to grant the Linnaean residents the special removal permits.

The council passed Clinton's ordinance 5-4, with all four CCA councilors opposed.

Sally Ackerman, a resident at the 36-42 Linnaean St. and 4-6 Washington Ave. building who had served as a spokesman for her neighbors in the past, declined comment last night on the case.

Vellucci called the Linnaean St. case "a monkey on our back" and said that despite his request for a moratorium on condo discussions, "We're trying to get rid of it."

CCA Councilor David Sullivan, one of the strongest supporters of the city's condo conversion ban, said that the moratorium was never really in effect.

In a prepared statement released March 16, Vellucci said, "I ask my colleagues on the council to take their condominium amendments and hold them until another day."

"Other components of our housing profile have been ignored two long while condo controls in particular have dominated the Council agenda," Vellucci stated.

Last night the four CCA councilors and Vellucci also gave preliminary approval to an ordinance sponsored by CCA councilor Saundra Graham which attempts to clarity the purpose of the anti-condo code passed in August 1979.

Residents who moved into rent controlled apartments after the original passage date are not allowed to purchase and occupy their homes as converted condominiums without a special permit from the rent control board, according to the Graham's amendment.

The rent board is currently appealing a recent decision by a Middlesex District Court judge who ruled that one post-1979 tenant could purchase and occupy her apartment without rent board permission.

Vellucci noted that his continued support for Graham's ordinance, necessary for it to gain final approval from the sharply divided council, is contingent on including a provision for limited equity ownership of rent controlled housing.

Under most limited equity arrangements used in other cities, residents purchasing apartments agree to limit the profits they might realize upon later resale, thus insuring that the homes can remain available for low and moderate income tenants.

In two weeks the council will consider giving final approval to the ordinances passed initially last night.