A tough crackdown on textile imports by the Reagan administration over the past 2 1/2 months has shut out almost $300 million worth of goods, from bargain-basement shirts to luxury gowns.

A coalition of retailers--who carried their complaints about the government measures to the administration yesterday--called the import restrictions "shocking and unprecedented . . . protectionist actions." They said that the restrictions have "disrupted the entire import and retail trade and jeopardized the strong recovery of retailing in the first quarter of this year."

In 56 separate actions, the administration has effectively frozen textile imports of specific categories of goods where shipments have been rising most rapidly.

The textile industry said the restrictions were needed after imports surged 22 percent over last year's levels during the first five months of 1983. Imports now account for 30 percent to 40 percent of all textiles sold in the United States, according to industry and union figures.

The retailers blamed the import restrictions on a lobbying campaign by the textile industry led by Sen. Strom Thurmond (R-S.C.), an influential textile state Republican, who took his appeal directly to President Regean.

In a "Dear Strom" letter signed "Ron," the president on June 29 promised "positive steps . . . in response to the 1983 import increases."

The import restrictions are "a significant step up . . . over the eight actions initiated by this date last year, and is equal to the total number of such actions taken during all of 1982," Reagan said.

The president established an interagency working group to study the textile problem and report to him by the end of the month. That group is headed by Walter Lenahan, a former foreign service officer who works as the textile czar in the Department of Commerce.

He also cited the 30 quotas his administration placed against imports from the Peoples Republic of China in Janauary after talks on a bilateral agreement broke down. A new round of talks is set for later this month in Geneva.

The quotas on textiles from China provides another illustration of the interrelations of international trade, as Peking retaliated by refusing to buy American cotton, soybeans and chemical fibers. The Chinese also have cut wheat purchases from America, which has angered U.S. farm groups.

On the textile front, the retail coalition said the new quotas violated the multifiber arrangements setting quotas for most textile-exporting nations and separate bilateral agreements the United States has with other overseas manufacturers. The Commerce Department, however, said these restrictions are allowed under America's textile agreements with other countries.

"I can understand why they the retailers are griping," said James A. Chapman Jr., president of the American Textile Manufacturers Association and chief executive officer of Inman Mills in Inman, S.C. "But the situation [on imports] is just out of control."