Oscar, Sydney and Wool in Chic Clothing

When Oscar de la Renta arrives in Australia this week -- for the grand bicentennial celebration in Sydney -- it will be his first visit Down Under. De la Renta has tried to go two other times; once his designs and models arrived even though he didn't.

That show made quite an impression. "I had a beautiful model then named Carla Araque, a Spanish girl. She was wearing a halter dress, and in the middle of the runway she stepped on her hem and the whole dress came down. She walked off the stage, her hands covering her breasts," said de la Renta, imitating the pose.

"There was a photograph of Carla in part of my dress on the front page of many newspapers across that vast country." Says de la Renta's assistant Jack Alexander of this year's show: "There will be no halter styles, or topless styles, this time."

Designer Donna Karan is the only other American designer to be featured in the show at the Sydney Opera House, which will be attended by the Prince and Princess of Wales. Bruce Oldfield, who created three of the dresses the princess will wear in Australia, at least one above the knee, and Jean Muir will represent Great Britain; Claude Montana, Sonia Rykiel and Kenzo will come from France; and Gianni Versace and Rosita and Tai Missoni will represent Italy. Australian designers showing with this international group are Wendy Heather, George Gross, Jill Fitzsimon, Stuart Membery, Adele Palmer, Marilyn Said and Barry Taffs. Designers were chosen by the International Wool Secretariat, the educational, promotional and marketing organization for wool growers in the southern hemisphere.

Surely everything shown will not be wool, but those pieces that are will likely be Australian wool, which is about 80 percent of all the wool used in clothing. History in the Remaking

The French have been selling clothes to les Americains for years. So what better place than the French Embassy for U.S. retailers to revel?

The embassy hosted a dinner and fashion show last week for the Associated Merchandising Corp., the largest retail merchandising, marketing and consulting organization in the world. AMC's annual meeting here lured top retailing executives from its stores around the country, including Bloomingdale's, Bullocks, Dayton Hudson, Federated, Strawbridge & Clothier, Goldsmith's, Higbee's and Washington's own Woodward & Lothrop.

A dinner followed a few warm speeches, one by the embassy's French trade officer Jean-Daniel Tordjman and another by AMC's CEO Lee Abraham, who was brave enough to do it en francais.

The fashion show celebrated "200 Years of French Fashion." The first flouncy outfit down the runway looked a little like a Christian Lacroix, but turned out to be a "Watteau style" dress from the 1730s. The costumes kept coming, in chronological order. Stunning re-creations of 18th- and 19th-century styles (before designers had famous names) were succeeded by legendary originals from the 20th century -- a Poiret evening gown, Chanel's jersey suit, Christian Dior's new look, the Mondrian dress by Yves Saint Laurent, a metal dress by Paco Rabanne. The music matched the time frame of the clothes, as did the hairstyling by Washington's Frenchman Bernard from Okyo.

This got everyone to thinking: Why are the French so terrific at designing clothes, anyway?

"It's because the French people really care about the appearance of things, about the way things are done," says Federated Vice Chairman Donald Stone. "And I'm sure that's why the French are so good at fashion -- presentation is so important."

"In France, there is a certain chic and taste that is marvelous. But I'll tell you, they were also the first to discover American sportswear," says Bloomingdale's Chairman Marvin Traub." -- Martha Sherrill Dailey Dexter's Second Skins

As many skiers already know, that navy and white undershirt hanging out from under Dexter Manley's uniform during the Minnesota game was LIFA polypropylene underwear. It's not that the Redskins never wore long johns before, only that Cardinal, the company that used to supply them, has gone out of business. That's why Jay Brunetti, Redskins equipment manager, contacted Helly-Hansen, makers of lIFA and other such products in Redmond, Wash., and ordered 100 pieces, Federal Express, before the Chicago game that preceded the Minnesota triumph. Polypropylene wicks dampness away from the skin, leaving it dry and warm.

Manley's wearing the shirt last Sunday "was the luck of the draw," said Brunetti. Both the new LIFA and the old Cardinal styles were put in the players' bag for the game and "Manley was the only one who decided to throw on the LIFA."

Coach Joe Gibbs also let a commercial nod slip into the skirmish. He was wearing a white turtleneck from Damart with the logo of the company inscribed in blue. "The coach likes turtlenecks and that was one of a sample sent by Damart,"explained Brunetti.

Meanwhile, in Boston, a group of nine Redskin fans wanted to emulate Manley, at least in dress, and contacted LIFA to get the appropriate bottom layer. Notes de la Mode

Most people would look on in horror if a glass of red wine was spilled on a white dress. Val Cook of Saks-Jandel admits that would be her normal reaction, too. But when it happened at the Maison Francaise recently to Lee Traub, wife of the chairman of Bloomingdale's, Cook could only muster, "I'd feel terrible except that I know that your Chanel dress is two years old and you have considerable access to others."

Out on the pike to do some fashion shopping this weekend? Rather than taking a fast food break, take a fashion boost from the Folk Dress and Textiles exhibit at Montgomery Community College (Rockville Campus, 51 Mannakee St.). The exhibit of costumes and textiles from around the world is open Saturdays in the college gallery from 11 to 2 p.m.

A fashion that many furriers and fashion stores missed this year was the shearling coat. By last weekend there were a few scattered pieces for men at Ralph Lauren's Polo shop, a couple of men's coats at Woodies and a few coats for women in the Back Room at Loehmann's. The best assortment now is available by mail, from French Creek Sheep & Wool Co., Elverson, Pa. 19520. And by the way, it has the Russian-style hat in shearling, with earflaps, too.