The Hayloft Dinner Theatre will end its contract with Actors Equity July 27, theater owner Frank Matthews said last week.

The termination of the agreement with the union leaves the Washington area with no Equity dinner theaters for the first time since the Hayloft was founded in 1971.

"There was absolutely no quarrel with the union," Matthews said. "It was merely a matter of remaining financially competitive with the rest of the area."

Matthews also cited factors other than economic ones for his decision. "We're finding we are getting very little response from non-Equity actors," he said, noting that under the Equity contract only 20 percent of the roles can be made available to nonunion actors.

Matthews also announced that he has hired Norman Aronovic, who ran the King's Jester Dinner Theatre until it closed last year, as the Hayloft's producer. Aronovic's first production will be "Little Shop of Horrors," which opens Aug. 12.

Tab Hunter, Nanette Fabray and Pat O'Brien were among the "name" actors who appeared in productions at the Hayloft during its Equity years. Matthews said the theater's return on star shows has been "dropping a bit recently ."

Asked if going non-Equity will affect the quality of Hayloft's productions, Matthews replied, "If it affects it a lot, I'll go back.

"It's a business decision," Matthews continued, "but I'm not doing this to cheapen the theater." Celebrity Improvisation

Rick London Stetelman has come up with a clever solution to filling a 10-minute gap in his play "Would You Care to Talk About It Jack?," which is about a New York stand-up comic and a psychiatrist who trade jobs. Throughout the play's run this week in the Washington Theatre Festival at Source Theatre, local celebrities will improvise a scene on the shrink's couch. Tomorrow it's WDCA-TV's Dick Dyszel, a k a Count Gore DeVol; Thursday, "Entertainment Tonight's" Peter Quinn Hackes; ; Friday, syndicated news correspondent Sarah McClendon; and Saturday, radio talk show host Larry King and WRC-TV's Steve Doocy and his wife Kathy.

Other highlights of the festival this week include tonight's performance of Ray P. Comeau's "Matter of Fact," a play about an AIDS victim who finds help and hope from an oddball group of friends and family, and Sunday's 10-minute play competition, featuring such tantalizing titles as "Gidget on Drugs," "Ask Aunt Polly" and "Meat." For complete festival details call 462-1073. Performing Arts Directory

Local set designer Matt Cooper is compiling a performing arts directory for the Washington area. Millie's, as the directory will be known, will be a sort of yellow pages of the local entertainment industry, with more than 200 categories, including actors, playwrights, dancers, musicians, technicians and public relations agents. Inclusion in the directory is free; for an application call 892-5228. 'Beehive' Hairdo Contest

It'll be the Battle of the Big Hairs Sunday at 7 p.m. when Arena Stage sponsors a Beehive contest in the Kreeger Theater, where the '60s musical revue "Beehive" runs through Aug. 24. Judging the competition to determine the most striking skyscraper-do will be Robin Weir, hairstylist for First Lady Nancy Reagan.

First prize is $200 and an '80s makeover at one of Weir's salons and second prize is two tickets to Arena's 1986-87 season. All contestants will receive as consolation two tickets to an Arena play next year and, probably the most useful prize, a can of Aquanet. Female and male contestants are welcome and wigs are acceptable. To register call 488-3300.

Postscript: Last Friday Arena sold 1,394 tickets to "Beehive," breaking its previous one-day sales record set last season by "Tartuffe." Odds and Ends

"Extran o Juguete ("The Toys"), by Argentine playwright Susana Torres Molina, has its United States premiere Friday at Gala Hispanic Theatre. The play opens this week in Spanish and will be performed in English on alternating weeks through Aug. 24 . . . Philadelphia's Wilma Theatre production of Czech playwright Pavel Kohout's adaptation of George Orwell's "1984" opens Saturday at the Kennedy Center's Terrace Theater . . . "Ma Rainey's Black Bottom" has been extended at the Studio Theatre through Aug. 3.