NEW YORK — Designs Inc., the chain selling only Levi Strauss products, said Monday it will alter the format in seven of its 58 stores by testing private label products this fall, primarily tops.

“It’s a small test, but it’s something we really have to do,” said Joel H. Reichman, president. “We’ve always been saying that we should increase our tops business.”

He said retailers typically sell three tops for each bottom, but at Designs, it’s the reverse.

Reichman said the move was not motivated by any concern about its future with Levi’s but was made to fill “some definite voids” in the store.

Private label shirts, sweaters, denims and possibly outerwear should be in units in New Hampshire and Massachusetts by late October or November.

The label being considered is Exclusively for Designs E.F.D.

Exterior store signs will be changed, since they say “Designs Exclusively Levi’s.”

The goal is for the stores to carry 30 percent private label goods. Depending on consumer response, more stores could become involved in the program.

“Whatever choices we make relating to private label and brand name merchandise, one of our major continuing strengths will be our association with Levi Strauss & Co.,” Reichman said.

A Levi’s spokeswoman said, about shipping Designs, “It’s business as usual.”

She said Levi’s expects no problems in its joint venture with Designs to open Original Levi’s stores. Under the agreement, which is still not final, Designs will open 35 to 50 stores in 11 Northeastern states in the next three to five years. Last month, Levi’s petitioned the Federal Trade Commission to make sure that an 1978 FTC consent order signed by Levi’s, which addressed price-fixing allegations, did not interfere with its retail plans. Levi’s is awaiting a response and noted it has no plans to open stores on its own, and said the filing was done to clear the way for its joint venture with Designs. If Levi’s opened its own stores, it could undermine growth with Designs.