The culinary arts are looking up in down-under kitchens

For years the Australian kitchen was labeled by travelers as a lost cause, characterized by stodgy meat pies, the salty gelatinous spread called vegemite, and the elegant but old-fashioned meringue and fresh-fruit dessert, the Pavlova.

But things have changed, and a visit to almost any large city in Australia proves to even the most skeptical diner that things are looking up down under.

In Melbourne, for example, this ''garden city'' at last count had over 1,300 restaurants. This is in part a response to heavy immigration since World War II, particularly of Greeks, Italians, Chinese, and Vietnamese.

But the real boon to restaurants was the 1956 Olympics, when chefs arrived to cook for their national teams. Some liked the city so much they stayed and opened restaurants.

Beverley Sutherland Smith, a Melbourne cookbook author and teacher, says Australians have started to travel more.

''They tour Europe for five or six weeks and find out what fine cooking is all about. Then when they come back, they won't accept second best,'' she says.

Mrs. Smith, who has written four cookbooks, has studied with Michel Guerard in France and Freddy Girardet in Switzerland. Her cooking classes are always booked a year in advance.

A restaurant like the Cliveden Room in the Melbourne Hilton reflects the sophisticated style of dining that Australians in large cities can now enjoy. The room itself has been reconstructed with the stained glass and wood paneling of a 19th-century mansion that was on the site before the hotel was built.

The meal might begin with a duckling pate from a recipe of Paul Bocuse, followed by perfectly cooked ravioli filled with lobster, and a scallop mousse.

Among the choices for the entree are barramundies, a delicious, firm-fleshed Australian fish, with fennel butter; medallion of veal with a dilled salmon sauce; or Chicken Supreme filled with brains and spinach.

Pastries on the dessert cart are rivaled only by the luscious fresh fruit from the region of Queensland in the north.

Australia is proud of its variety of magnificent seafood, which includes scallops and crayfish from the island of Tasmania, giant prawns from Queensland, and Sydney's famous rock oysters.

The Pacific and Indian Oceans are fished for bass, bream, cod, kingfish, mackerel, mullet, perch, snook, and whiting - to mention only some of the varieties.

''At our Victoria market,'' said Mrs. Smith, ''we have access to fresh fish flown in from all over the country. Seafood is very popular, and one of the trends is to cook fish with fruits, like whiting with grapes, for example.''

The enthusiasm for food and fine cooking in Melbourne is perhaps nowhere better illustrated than in the Hill of Content Bookshop on Bourke Street, where a longtime employee, Claire Kearney, tests the recipes in cookbooks before putting them on the shelf.

''The most popular cookbooks here are the ones published in America,'' she says. ''Last year our biggest seller was 'Cooking the Nouvelle Cuisine in America,' by Michele Urvater and David Liederman. We sold 300 copies.

''Some of the finest restaurants cook from it. People also make the dishes at home, for having dinner parties is the big thing in Melbourne.''

Dinner parties notwithstanding, the barbecue is still a strong contender for the most popular form of entertaining. ''Aussie barbies,'' as they are affectionately called by the locals, are far from the rough-and-ready outback affairs where roasted kangaroo, damper (an ash cake made of flour and water), and billy tea are featured.

Instead, they are casual but sophisticated events where the steaks are likely to be marinated in a mixture of Worcestershire and soy sauce, mustard, fresh ginger, and garlic before they are grilled.

But nowhere is the eclecticism of contemporary Australian cooking more apparent than in the vast array of salads served with the grilled fish or meat.

Australians love to invent salads, taking bean sprouts from the Chinese, fennel from the Italians, and bulgur wheat from the Middle East, then tossing them all together with an interesting dressing.

The variations are endless, and it is not uncommon for a guest to find himself faced with the tough decision of choosing from six or eight salads at an Aussie barbie.

This simple smoked-fish recipe is from ''Australian Fish Cooking,'' by Grant Blackman (Melbourne, 1978). Smoked Fish Flan 1 9-inch unbaked pie pastry, pricked 1 1/3 cups heavy cream or half-and-half 1 tablespoon French-style mustard 1 1/2 teaspoons capers, chopped 2 large eggs, lightly beaten Salt to taste Freshly ground black pepper 1/2 pound smoked fish, flaked

Bake pie pastry 10 minutes in an oven preheated to 425 degrees F. Set aside. Combine cream, mustard, capers, eggs, salt, and pepper. No salt needed if smoked fish is fairly salty.

Spread flaked fish evenly on piecrust. Top with cream mixture and bake in an oven preheated to 350 degrees F. until custard is set and top slightly browned, 45 to 50 minutes.

Leave at room temperature about 5 minutes before slicing. Serves 4 to 6.