Arlington County housing advocates will turn to the Virginia legislature when it convenes in January for help in creating the housing finance agency that county voters rejected last month.

Backers say an agency is needed to preserve Arlington's supply of low- and moderate-income housing, which is deteriorating or being converted to condominiums. Opponents raise the specter of public housing and of a powerful authority virtually independent of county control.

In November, the proposal to create a redevelopment and housing authority was defeated by nearly 11,000 votes. It was to be similar to those in 29 other Virginia cities and counties.

County staff workers are preparing proposed state legislation that would create an agency with only the authority to finance housing, said Hank Leavitt, administrative aide to the county manager. The county board and the five-member Arlington delegation to the legislature will hold a public work session soon on this plan.

State legislators approved a measure in the 1982 session that established a housing financing authority in Buchanan County in southwestern Virginia. State Del. James F. Almand said the Buchanan precedent would be "helpful" to backers of an Arlington bill.

Almand, Arlington Democrat and a leading proponent of the housing finance authority, said another method of obtaining housing funds for the county would be to amend the state's Industrial Development Act to allow issuance of tax-exempt bonds to finance low- and moderate-income housing. Approval of such a measure would automatically extend that power to local jurisdictions, including Arlington, that have Industrial Development Authorities.

Almand may propose introduction of both the amendment to the Industrial Development Act and a bill to create an Arlington agency. He said the delegation could place one measure before the House of Delegates and the other in the Senate, in the hope that one will pass during the 30-day session.

Almand's effort is expected to have the backing of the five-member Arlington County Board, which will have a Democratic majority when Mary Margaret Whipple takes office Jan. l. Whipple, who supports a county housing authority, defeated the incumbent chairman, Republican Stephen H. Detwiler, who campaigned against the proposal.

The November referendum question calling for a county housing authority "was a complicated issue" about which voters were not adequately informed and apparently feared would cost too much, said Melodee Bawden, supervisor of the county's rent assistance office.

Whipple and other officials who want a housing finance agency say they are seeking only the power to finance rental housing and do not want public housing owned and operated by the county.

"Our intention was to limit an agency's uses to financing. This could help preserve the moderate-cost housing that exists in the county," said Whippel.

"Arlington has a number of older garden apartments that need rehabilitation," said Almand. If owners must pay the high market rates on renovation loans, they either will have to raise rents or sell the property to developers, who in most cases convert the property to condominiums. Tax-exempt bonds could provide lower interest loans for owners of rental units, he added.

Board vice-chairman Dorothy Grotos, a Republican, is not reassured. She said the effort to establish a housing agency through state legislative action is "outrageous" and "insensitive to voters in Arlington County."

Grotos said present proponents of a housing authority "may not always be around and somebody else may use the authority" to create public housing programs.

Bawden estimated that 9,000 of Arlington's 150,000 residents have incomes that qualify them for housing assistance. Most of them are renters. To qualify a single person can have an income of up to $15,000 annually while a four-person household can earn up to $21,000; the limit rises according to the number of people in the family.