The chairman of the bargaining unit for rank-and-file D.C. police officers said yesterday that the city will have to "abandon" its hiring standards if it is to swear in more than 180 police officers by Oct. 1, as ordered by a congressional subcommittee.

The House D.C. Appropriations subcommittee last week threatened to withhold the entire $336 million first installment of the city's federal payment for the 1983 fiscal year, which begins Oct. 1, if the city does not hire the additional police officers by that date.

But Gary Hankins, bargaining chairman for the Fraternal Order of Police, contended yesterday that the deadline will force the department to recruit candidates who might otherwise fail to pass personal background and medical checks.

"It is impossible for the city to process enough applicants to hire the number necessary . . . without abandoning all standards," Hankins said in a letter delivered yesterday to the office of Rep. Julian Dixon (D-Calif.), chairman of the subcommittee. "I am sure you will agree it will do much more harm than good to hire unqualified people to protect our community."

Hankins suggested that instead of trying to hire the additional officers on such short notice, the city could instead have current officers work overtime to provide more of a presence on Washington streets -- an idea that the subcommittee has frowned on in the past.

The police department's personnel director also expressed concern yesterday over whether the department will be able to meet the Oct. 1 deadline.

"If Congress extends the time, then we should be okay," said Capt. Donald H. Christian. "But if they're just going to be hard-line and say it has to be by Oct. 1, then that causes me some concern. We're talking about time."

Christian said his office is proceeding as though there will be no extension of the deadline, and is "not going to short-cut" any of the background or medical checks to meet the congressional mandate.

He said his office has increased the number of investigators doing background checks on recruits from 13 to 20. The additional investigators were taken off street patrols and other details, he said.

City Administrator Elijah B. Rogers said he would have no comment on the FOP letter because he had not seen it, but added that he has been assured by Police Chief Maurice T. Turner Jr. that the Oct. 1 deadline would be met without any lessening of standards.

The District receives a federal payment each year in lieu of taxes and other revenues lost because of the city's status as the seat of national government.

A total payment of $361 million has been authorized for the fiscal year beginning Oct. 1, but pending before the Appropriations subcommittee is a request for only $336 million. It is this money that the subcommittee has threatened to hold up.

The House subcommittee first directed the city to increase the size of the police force to 3,880 officers in November 1980. The city never reached that figure, however, and currently there are 3,695 officers on the force, according to the subcommittee.

Yesterday, the police department swore in 27 new recruits, and it plans to hire and start training an additional 60 by Sept. 7, Rogers said. He said an additional 94 officers either will be in training by Sept. 30 or will have received letters of commitment offering them jobs.

Subcommittee chairman Dixon was out of the country yesterday and could not be reached for comment. Another subcommittee member, Rep. Lawrence Coughlin (R-Pa), said the committee at this point still intends to hold the District responsible for hiring the officers by Oct. 1 and using "the highest of standards" to recruit them.

Coughlin accused the city of "dillydallying" for the past two years in fulfilling the subcommittee directive.