In front of a closed coffee shop called The American Dream on Seventh Avenue in the heart of New York's garment district yesterday, four designers and salesmen were peddling crinkly gauze separates from a metal rack and a card table. It was a fresh twist in creative merchandising by fashion designers attempting to counter the virtual shutdown of business at the height of the resort and holiday buying season because of a massive power failure. Consolidated Edison predicted it could be Monday before power is restored to the area.

"We've been zonked," said Jim Robbins, head of the huge sportswear manufacturing business called Crazy Horse with showrooms on Seventh Avenue. Buyers attempting to reach Crazy Horse and other manufacturers in the garment district have been shut out since Wednesday morning when a 68-year-old water main burst and created a day-long inferno in an underground bank of transformers. Power in the area was shut off from Herald Square to Times Square, virtually paralyzing the garment business at the height of one of its important buying seasons. Both Macy's and Gimbel's were among the businesses closed.

"For us this market week could mean as much as $1 million to $2 million in business," said Robbins. "Buyers were in town for their fourth quarter needs," he added, referring to the holiday and early spring clothes that are sold in stores from December through February. "My men will have to do some tall traveling to make up for it."

The New York fashion industry, the city's biggest employer, which generates about $15 billion annually, remained at a virtual standstill. However, a few buildings on the west side of Seventh Avenue, those housing high-ticket, designer-label merchandise, escaped the calamity and continued to function from a power source independent of the rest of the garment district.

"We're unscathed," said Calvin Klein by phone yesterday. On Wednesday, Klein ordered a fleet of limousines to take his workers out of the garment district at the end of the day. "I wanted to get everyone out of the place. We were frightened of the looting," said Klein. In fact, police reported none.

During the day there was chaos as buyers, manufacturers, seamstresses and others gathered in front of buildings on Seventh Avenue and Broadway, uncertain how long their schedules would be delayed. "I simply assumed it didn't affect me," said Aniko Gaal, Garfinckel's fashion director, who said the crowd, as well as fire trucks and mounted police, was like "a ticker-tape parade." Business was brisk as instant entrepreneurs peddled coffee and doughnuts from makeshift stands.

Bridal designer Ada Athanassiou arrived at her Seventh Avenue building "terrified," picturing brides scheduled to go down the aisle this weekend with their wedding dresses locked in her workrooms. She hoped "the lights would go on any minute. I couldn't even call my clients--my address book was locked in my desk." Building employes told her she could get into her showroom "with a note from the father or the bride or the priest"--but she never got in.

Guards kept David Pressman, marketing director for Perry Ellis, from getting to Ellis' Seventh Avenue showroom to keep his early appointments Wednesday morning. By the end of the day Pressman had "bribed a few people" and gotten into the Ellis showroom. Using flashlights--lights and air conditioning were off--he and helpers packed up clothing samples and took them in a company truck to the Sheraton City Squire Hotel, where the Perry Ellis company set up makeshift selling space.

Pressman placed an ad in Women's Wear Daily, the trade paper, and called buyers at their New York hotels to alert them to the new location. It was business as usual, almost, by yesterday morning. Last night, the clothes were carried by armored car to a security company's vault, to be returned to the hotel this morning. "These are original samples. We don't even have duplicates for some of the designs," said publicity director Karen Fortier, explaining the heavy-duty security.

Alexander Julian, whose showroom for women's designs is in the shutdown area, quickly set up selling space a few blocks away where he normally sells clothing for men. "Seventh Avenue was like a giant tea dance with all the fashion victims devotees outside," said Michael Winter, who runs Julian's division for women's clothes. Winter needed his appointment book in his showroom, but a guard kept him from entering. "But with a little cash . . ." he said with a laugh. Once upstairs, Winter gathered up 20 samples, order blanks and posters and came down and dumped them in his Volkswagen Rabbit convertible. He marked the posters with the address of his temporary showroom and had them posted at various sites--on mailboxes, buildings and hotel lobbies where buyers were staying. "It looks like we planned for the blackout. Business was terrific," said Winter. "We may have been better off than if this whole thing hadn't happened."

Hecht's vice president Nancy Chistolini at first thought the power outage was no more serious than another time earlier this week when lights were off in one showroom. But once it was clear that the firms she needed to see were closed at least for the day, she headed to Saks Fifth Avenue "to check the competition."

Woodward & Lothrop executive John Henderson and the 30 fashion buyers he supervises also made the rounds of New York stores. "My first appointment was with a vendor manufacturer at Gross' coffee shop on Seventh Avenue at 9 o'clock," said Henderson, who never got there. "The streets were like a carnival. I saw people I haven't seen in years," he said. When it became clear he could not keep his appointments, Henderson headed for the new deluxe 57th Street shopping mall, Trump Tower, then down to the just-opened shopping area near Fulton Street. "I haven't walked that much in 15 years," said Henderson, who nevertheless said the excursion did him a lot of good. "We don't spend enough time looking at the competition."

"Isn't it my luck. I'm in the building with the power on," teased Bill Blass, who was working on a television commercial. "I've been on the road for the last six days. I could really use a little time off."