There's more to Portuguese wines than port and madeira or Mateus and Lancers, though a shopping tour of Washington area wine shops does little to confirm this.

From the handful of table wines locally available one would not conclude that Portugal (not quite the size or population of Ohio) produces nearly twice as much wine as the United States, or that 15 percent of its population makes its living from wine.

This all might be tossed off with a shrug if it weren't for one thing: Portuguese wines are among the best and cheapest everyday wines I know of. Even the popular rose's are decent wines, though not quite the bargains most of the whites and red are. And the reds can sometimes rise to formidable heights. British writer Hugh Johnson recalls one that "would not disgrace one of the famous vineyards of France," and I have had two or three that belong in that class.

So why aren't more of them available in Washington? Probably for several reasons. Only the largest shippers, those who handle the brands made in sufficient quantity to sustain considerable advertising, regularly bring wines into the United States. Unfortunately, these are not always Portugal's best.

Also, for most of us accustomed to California, German, Italian and French bottlings, the Portuguese labels don't offer much information about what's inside. This puts off customers and wine merchants.

What one finds on labels is a brand name oir simply "red wine" or "white wine." Grape varieties and vineyard names are rarely used (the wines are always blends); estate bottling is negliglble, and vintage dates, when they appear at all, need to be approached with an open mind.

No wonder the late Frank Schoonmaker wrote that "one of the charms of Portuguese table wines (is) that they do not take themselves seriously."

True, there are certain government supervised areas, such as the regions set apart under France's Appellation Controlee laws, where specific standards must be met. But these names on a label don't guarantee that the quality of the wine is any better, or as good, as brand name wines that may come from anywhere in the country.

Another problem is promotion, something the Portuguese have done little about until recently. However, I doubt that it would have accomplished much if they had begun sooner because until the prices of French and American wines began to skyrocket, the competition and tradition were too much to allow them a foothold. But now the time is ripe.

With the prices of the better French and American wines soaring to new heights and petits chateaux ballooning to $5 or $6, good, straightforward Portuguese wines at$2 to $3 have become superb buys. Some are so cheap, particularly when bought by the case, that they rival California, French and Italian jug prices. And many of them are better wines.

Nearly all them are ready to drink when purchased, so the impatient or casual drinker doesn't need to pass them by. They do seem to benefit from decanting about half an hour before serving.

Of the wines I found in Washington, the reds are by far the most impressive. In a series of tastings over the past few months, their quality and price surprised and cheered those who were tasting them for the first time and reconfirmed their pleasures to those who had sampled them before.

Best buys of those tasted is the non-vintage Dao, Grao Vasco, a bargain at $2.25 to $2.50, the price in most local stores. It is an even finer value at MacArthur fo $1.99. Fruity, well-balanced and reminiscent of a lesser Burgundy, it is capable of holding its own with hamburgers, steaks or something a bit more pretentious.

An even better wine at a slightly higher price is the 1971 Dao, Conde de Satar ($2.99). It shows the glycerin-smoothness and intensity the wine books claim for Daos and has lots of fruit and flavor to go with it.

The champion of them all, however, is the latest in a series of well-aged, relatively inexpensive ($4.99) reds released by the large firm of Carvalho, Ribeiro and Ferreira. It is their 1955 Vinho Tinto, Garrafeira (it means "Private Cellar" and is affixed only to their best stock), a soft, flavorful and big-bodied wine that displays all the character and charm of maturity.

Having had two earlier vintages of the same wine, 1945 and 1949 (some of which I'm still hoarding), I am convinced the Garrafeiras would be tough competition for some better known and far more expensive French wines.

Of the other three reds I found, our tasters preferred, in this order, 1969 Alianca, Caves Alianca ($2.99), 1966 Serradayres ($2.99) and, a distant sixth, non-vintage Dao, C. da Silva ($1.69).

All the wines save the Alianca and da Silva Dao are available at a number of local stores; these two I could find only at Central.

The whites didn't fare nearly as well as the reds. The main reason for this, I think, is their age. From my experience Portuguese whites should be drunk young, before they are three or four years old. Two of the half-dozen we tried were over six while three of the others, being non-vintage, were impossible to pinpoint.

The 1972 Dao, Conde de Santar ($2.99), turned out the best; it showed good fruit, flavor and body and would be a fine companion for fish, seafood and chicken dishes.

The white Mateus ($2.99) found considerable flavor among several of our tasters for its flavor and smoothness but lost out to others who disliked its sweetness.

Carvalho, Ribeiro and Ferreira's Vinho Blanco Reserva ($3.19, Morris Miller) and the same firm's 1970 Serradayres ($2.99), came out about equal, with the former distinguished by its balance and light flavor and the latter by its flinty tartness. Served well chilled they could do quite well with fish and chips, fried chicken and the like.

The high price ($3.69) and the spritzy, very sweet, pop-like taste of the 1976 Lancers white combined to leave it few boosters among our groups. The non-vintage Grao Vasco white ($1.99 to $2.50) was the least impressive of all.

Two other, quite different Portuguese wines also turned up. These are vinhos verdes ("green wines"). Their curious name comes not from their color - they can be red as well as white - but from their youthful, fresh stryle. They are barely alcoholic (9 percent), tart and, at least in Portugal, slightly spritzy.

The two I tasted, both whites, Aveleda ($3.19) and Ravel ($2.69), left me with the feeling that vinhos verdes are best left for your visit to Portugal.

Missing from local shelves are the lovely fortified dessert wines, Moscatel de Setubal. At one time a few of the younger ones appeared here, though the older bottlings have always been hard to find. But keep an eye open for them because even with their age and scarcity, good Setubals can cost only $4 or $5.