After a period of relative price breaks for consumers, meat prices have begun rising sharply here and across the nation and will rise even more next year.

Increases of as much as 30 percent for pork, 18 percent for poultry and 16 percent for beef are predicted for 1981 by government and industry analysts. And the price of hamburger -- the mainstay of many a family's dinner -- will also rise dramatically despite a trend last spring toward lower prices for ground beef.

"I think shoppers will be shocked by the meat prices they see," said Dennis Steadman, director of agricultural services for Chase Econometrics, an economic forecasting firm.

The price increases reflect a number of factors, but chiefly the cumulative effect of production cutbacks, grain exports and last summer's drought.

Some of the increases already are in effect at supermarkets. Although there are variations from store to store and city to city, bacon rose 29 percent, from $1.27 a pound to $1.64, between June and October, according to national retail surveys made by the Bureau of Labor Statistics. Chuck roast has gone up 7.5 percent, from $1.73 a pound to $1.86. Whole chicken has jumped 23 percent, from 64 cents a pound to 79 cents a pound. Some other poultry products, however, have gone up less than expected.

The pattern of price changes now sweeping the country basically reaches all consumers, no matter where they live or shop.Washington-area prices since June have climbed 10 to 20 cents a pound for many meats and poultry, and store retailers say they will raise prices again in the weeks ahead as their wholesale prices go up.

The present round of meat price increases already has outstripped the rate of inflation in some parts of the nation. In the Washington area, for example, the most recent Consumer Price Index shows that meats, poultry and fish rose 13.5 percent over the last year, compared to 11.8 percent for all consumer prices measured by the index. The average increase for the nation as a whole shows price increases for meats, poultry and fish lagging slightly behind the rate of inflation, but that could change over the next several months as meat prices continue to rise.

Hamburger is among the beef products that will increase the most, economists said. Last spring, ground beef declined as much as 20 cents a pound in the aftermath of the credit crunch triggered by government efforts to tame inflation.

But the price rebounded during the summer and regular ground beef now is $1.69 a pound at many local supermarkets, the same as it was before the spring dip.

Here is a summary of the meat price forecast from the U.S. Agriculture Department:

Beef is expected to sell at retail grocery stores for an average $2.73 a pound for a composite of all beef cuts, ranging from hamburger to filet mignon, for all of 1981, compared to this year's average of $2.39. That represents an increase of 14.1 percent, but the increases are expected to range from a high of about 16 percent for hamburger to a low of about 12 percent for fancy steaks.

Pork will average about $1.82 a pound, based on a composite of all cuts for 1981, compared to this year's average of $1.40 a pound. That represents an increase of 30 percent.

Poultry will cost more, too. Chicken that cost an average 70 cents a pound this year may cost 83 cents a pound next year.

Consumers faced with higher meat prices are expected to adjust rather than boycott as they did during the early 1970s.

"People are too worn down by inflation and constant price increases to boycott." said Charlotte Newton, president of the Virginia Citizens Consumer Council Inc. "And besides, we found out during the last boycott that it just raised prices in the long run because they [the producers] cut supplies."

Newton said that consumers generally "will substitute and learn to get by with less . . . in our family, for instance, we now have a meatless meal once a week. And I guess we could do that twice a week."

Statistics on consumption indicate that the Newtons are among a growing number of people who have cut back on beef. The amount of beef eaten by Americans increased steadily until 1976 when it reached 95.7 pounds per year. But it has declined each year since then: 93.2 pounds in 1977, 88.8 pounds in 1978, 79.6 pounds in 1979. The amount this year is expected to drop to 78.5 pounds.

In place of beef, consumers have been eating more of other kinds of protein foods. The amount of pork eaten by each person has increased from 54.6 pounds in 1976 to an expected 68.8 pounds in 1980. Poultry consumption has jumped from 52.5 pounds per person in 1976 to 62.3 pounds predicted for this year.

Pork and poultry generally cost less than beef.

Economics said that increases in meat prices this year have softened by unusually large supplies. Until recent months pork has been plentiful, and pork prices unusually low. Pork supplies are shrinking, however, as producers, stung by high-priced grain bills and other rising production costs, trim herds and try to boost income.

Summer drought, which destroyed crops and left the U.S. with 17 percent less corn than expected, helped push up the cost of feeding all animals -- pigs, chickens and cows. In addition, grain exports to other countries where weather damaged crops has also helped push up U.S. producer feeding costs.