Dissatisfied with the American and Japanese "inadequate" position in the Tokyo Round of trade liberalisation talks, the nine-member European Economic Community plans to inform American negotiators in Geneva today of a detailed lost of products on which the EEC is considering withdrawing tariff concessions offered earlier this year, according to diplomatic sources here at Common Market headquarters.

The secret lost, drawn up at a closed-door session of European trade officials here last Friday, sets out the areas in which a more restrictive European stance will result if the Carter administration and the Japanese government do not respond to Common Market demands for greater tariff concessions.

Items on the EEC list, which is expected to be revealed to Japanese and other Tokyo Round Participants before the weekend, include refined petroleum products, fertillizers and no less than 21 items in the chemical sector, according to informed policy aides here.

The new EEC move is seen here as a measure of the Common Market's disappointment at the apparent reluctance of the Carter administration to provide "significant" improvements in its own trade concessions tabled in the Geneva talks. These improvements were demanded by Sir Roy Denman, the top European trade negotiator, in talks held in Geneva earlier this month with Robert Strauss, the president's special trade representative.

"So far we have had no indication that the U.S.A. will make these improvements, say trade officials. Their main dispute with Washington centers on the so-called "exceptions" - products the U.S. is exempting from its general 40 percent tariff reduction proposals.

The EEC product list, considered as a counter-measure to U.S. exceptions, is described here as "the first line of defense" against the shortcomings in the American position. It is extensive.According to diplomatic sources, besides the items outlined earlier, it applies to goods in the following sectors: paper and wood, shoes, glass, nonferous metals, mechanical and electrical equipment, electronic goods, cars, zip-fasteners, cutlery and ceramics, leather and hides.

However, EEC officials say, the move is "not provocative." They insist the list was drawn up only after "careful study and evaluation of the real value of offers made by our trade partners," another way of saying the U.S. and Japan. Officials at the Common Market, which has offered a 40 percent reduction, argue that because of American exceptions, the proposed U.S. trade package is worth only some 30 percent to Europe.

But senior American officials contacted here protest that "there's more in our package than the EEC give us credit for," nothing that exceptions on items such as oil and specialty steels are more than offset by much greater liberalization on major market items such as automobiles.